Improve child validation wording from feedback.

This implements suggestions from discussions in issue #161.

Author: handrews

jsonschema-validation.xml

@@ -179,15 +179,26 @@
 
             <section title="Validation of primitive types and child values">
                 <t>
-                    Two of the primitive types, array and object, allow for child values.  The validation of
-                    the primitive type is considered separately from the validation of child instances.
+                    Two of the primitive types, array and object, allow for child values.
+                    The validation of the primitive type is considered separately from
+                    the validation of child instances.
                 </t>
                 <t>
-                    For arrays, primitive type validation consists of validating restrictions on length.
+                    For arrays, primitive type validation consists of validating
+                    restrictions on length with "minItems" and "maxItems", while
+                    "items" and "additionalItems" determine which subschemas apply
+                    to which elements of the array.  In addition, "uniqueItems"
+                    and "contains" validate array contents as a whole.
                 </t>
                 <t>
-                    For objects, primitive type validation consists of validating restrictions on the presence
-                    or absence of property names.
+                    For objects, primitive type validation consists of validating
+                    restrictions on which and how many properties appear with
+                    "required", "minProperties", "maxProperties", "propertyNames",
+                    and the string array form of "dependencies", while "properties",
+                    "patternProperties", and "additionalProperties" determine which
+                    subschemas apply to which object property values.
+                    In addition, the schema form of "dependencies" validates the
+                    object as a whole based on the presence of specific property names.
                 </t>
             </section>
 
@@ -335,8 +346,8 @@
                     If absent, it can be considered present with an empty schema.
                 </t>
                 <t>
-                    This keyword controls child instance validation.  Validation of the
-                    primitive instance type against this keyword always succeeds.
+                    This keyword determines how child instances validate for arrays,
+                    and does not directly validate the immediate instance itself.
                 </t>
                 <t>
                     If "items" is a schema, child validation succeeds if all elements
@@ -357,8 +368,8 @@
                     If absent, it can be considered present with an empty schema.
                 </t>
                 <t>
-                    This keyword controls child instance validation.  Validation of the
-                    primitive instance type against this keyword always succeeds.
+                    This keyword determines how child instances validate for arrays,
+                    and does not directly validate the immediate instance itself.
                 </t>
                 <t>
                     If "items" is an array of schemas, child validation succeeds
@@ -473,16 +484,17 @@
                     MUST be a valid JSON Schema.
                 </t>
                 <t>
-                    If absent, it can be considered the same as an empty object.
+                    If absent, it can be considered the same as an empty schema.
                 </t>
                 <t>
-                    This keyword controls child instance validation.  Validation of the
-                    primitive instance type against this keyword always succeeds.
+                    This keyword determines how child instances validate for objects,
+                    and does not directly validate the immediate instance itself.
                 </t>
                 <t>
                     Child validation succeeds if, for each name that appears in both
-                    the instance and as a name within this keyword's value, the instance
-                    value successfully validates against the corresponding schema.
+                    the instance and as a name within this keyword's value, the child
+                    instance for that name successfully validates against the
+                    corresponding schema.
                 </t>
             </section>
 
@@ -494,11 +506,13 @@
                     MUST be a valid JSON Schema.
                 </t>
                 <t>
-                    If absent, it can be considered the same as an empty object.
+                    If absent, it can be considered the same as an empty schema.
                 </t>
                 <t>
-                    This keyword controls child instance validation.  Validation of the
-                    primitive instance type against this keyword always succeeds.
+                    This keyword determines how child instances validate for objects,
+                    and does not directly validate the immediate instance itself.
+                    Validation of the primitive instance type against this keyword
+                    always succeeds.
                 </t>
                 <t>
                     Child validation succeeds if, for each instance name that matches any
@@ -517,8 +531,8 @@
                     an empty schema as a value.
                 </t>
                 <t>
-                    This keyword controls child instance validation.  Validation of the
-                    primitive instance type against this keyword always succeeds.
+                    This keyword determines how child instances validate for objects,
+                    and does not directly validate the immediate instance itself.
                 </t>
                 <t>
                     Child validation with "additionalProperties" applies only to the child