Bugs/564 fix maven raml builder plugin

[Riduidel]

Fixes #564 by allowing elements from inner classes to be referenced in annotation. The following are supported :

• direct field access
• access to field declared in an inner class or interface The following are not supported
• access to field declared in another class, even if in the same package
• access to a class defined from an expression (which can't happen, but is nevertheless considered as valid by javaparser)

Notice using fields from other compilation units would be way harder, as they are not loaded by javaparser

[cescoffier]

Looks good to me !

@barjo is it ok for you ?

[cescoffier]

thanks, merged !