Add note about missing classes on Android

Fixes: #36

Author: mpkorstanje

README.md

@@ -120,6 +120,12 @@ Feature: Examples Tables
 <testcase classname="Examples Tables" name="Eating &lt;color&gt; cucumbers - #1.2: Eating green cucumbers" />
 <testcase classname="Examples Tables" name="Eating &lt;color&gt; cucumbers - #1.3: Eating blue cucumbers" />
 ```
+
+## Android
+
+The Android SDK does not include `javax.xml.stream.XMLOutputFactory`. This and other missing `java.xml.stream.*`
+dependencies can be provided by adding `com.fasterxml:aalto-xml` to your dependencies. 
+
 ## Contributing
 
 Each language implementation validates itself against the examples in the