Update on karma

This commit still does not build, but contains a significant
architectural change. struct c_symbol and its derivatives were removed.
To little information for future semantic analysis was in these
structures. Instead, the raw c_c_declaration would be used and a
skeleton traverse_c_ast.{h,cpp} were created for future analysis. Note:
the only errors produced are link-time errors due to the
non-implementation of some functions (yet).