Clang-based parser of C++ source to automatically generate XML API description

[PetrPPetrov]

Create a Clang-based parser of C++ sources (or headers) to automatically generate XML API description.
So, implementing this issue will allow possibility to fully automatically create C-API for existing libraries.

[PetrPPetrov]

Clang (LLVM) provides API for accessing C++ class declarations, method and function declarations, etc.