[skip changelog] Correct lib name specification re: leading/trailing space (#779)

Leading and trailing space is correctly trimmed on all fields of library.properties, including name.

The unnecessary extra verbosity in the name specification may cause people to miss the other important restrictions.

Author: per1234

docs/library-specification.md

@@ -29,7 +29,7 @@ This file allows the *Library Manager* to search and install a library and its d
 
 The library.properties file is a key=value properties list. Every field in this file is UTF-8 encoded. Unless noted otherwise below, **all fields are required**. The available fields are:
 
-* **name** - the name of the library. Library names must contain only basic letters (`A`-`Z` or `a`-`z`) and numbers (`0`-`9`), spaces (` `), underscores (`_`), dots (`.`) and dashes (`-`). It cannot start or end with a space, and also it cannot start with a number. Note that libraries with a `name` value starting with `Arduino` will no longer be allowed [addition to the Library Manager index](https://github.com/arduino/Arduino/wiki/Library-Manager-FAQ) as these names are now reserved for official Arduino libraries.
+* **name** - the name of the library. Library names must contain only basic letters (`A`-`Z` or `a`-`z`) and numbers (`0`-`9`), spaces (` `), underscores (`_`), dots (`.`) and dashes (`-`). They cannot start with a number. Note that libraries with a `name` value starting with `Arduino` will no longer be allowed [addition to the Library Manager index](https://github.com/arduino/Arduino/wiki/Library-Manager-FAQ) as these names are now reserved for official Arduino libraries.
 * **version** - version of the library. Version should be [semver](http://semver.org/) compliant. 1.2.0 is correct; 1.2 is accepted; r5, 003, 1.1c are invalid
 * **author** - name/nickname of the authors and their email addresses (not mandatory) separated by comma ","
 * **maintainer** - name and email of the maintainer