First version of clang parser

Hi, 
the clang paser is now in a semi usable state. Together with the clang_integration branch from
https://github.com/jmachowinski/orogen it is possible to generate correct tlbs for base types.

Note that there are still some hard coded paths in 
bindings/ruby/lib/typelib/clang.rb.

Please test and review these changed.
Greetings
   Janosch


??? Since you guys actually did not build an importer, I'd like to know why you change the importer API.