REST interface scanner code improvement

[ok2c]

@arturobernalg I reworked some of your REST interface scanning code and made it use core parsing and formatting routines where available. Please review.

[arturobernalg]

@arturobernalg I reworked some of your REST interface scanning code and made it use core parsing and formatting routines where available. Please review.

@ok2c
Looks good overall.

Should this use producesContentTypes instead? @produces maps to Accept; @consumes should only drive the request entity Content-Type.

[ok2c]

@arturobernalg I suspect the current implementation of @Produces and @Consumes is wrong but this is a subject for a subsequent change-set. I wanted to make sure all your original tests still passed after the refactoring.