Add documentation to the processor class.
Copied from the Eclipse plugin help files, now that they reside in the project to which they belong.
Fixed javadoc
Merge branch '2.1-dev' of github.com:thymeleaf/thymeleaf into 2.1-dev

Conflicts:
	src/main/java/org/thymeleaf/standard/processor/attr/StandardAssertAttrProcessor.java
Reference schema file.
Merge remote-tracking branch 'github/2.1-dev' into 2.1-dev
Closes #227. Added method randomAlphanumeric() in #strings object.
Added StandardDOMSelectorFragmentSpec