Replace custom ansi-c parser with Clang

[nemerle]

This would get us full c/c++ header parsing, and we could add comment parsing as means of providing additional knowledge to boomerang engine.

[ceeac]

The issue is that the language recognized by AnsiCParser is not C, but a language providing symbol location and signature information that happens to be similar to C. IMO it would be a better idea to provide/design a file format for signatures and symbol information and then build a simple tool based on clang that converts header files to this file format. This way, we don't have to build clang into the decompiler.