Partial commit, converting to FeatureMap.

Also adding Control.Lens for convenience, we'll see how it goes.
It should make an improvement when updating records.
More fixes for FeatureMap
Commenting out the advanced string lexing.

It's wrong, but a bit troublesome to make it work.
Adding segregated FeatureMap type.
Text support in lexer/ast.
Updated to use Text and HashMap.
Merge branch 'class_ast_maps'

Conflicts:
	Language/Eiffel/Parser/Lex.x