Implement new classes:
* stdext::any => ligher replacement for boost::any
* stdext::packed_any => like any but optimized to use less memory
* stdext::shared_object => ligher replacement for std::shared_ptr
* stdext::shared_object_ptr => replacement for boost::intrusive_ptr
* stdext::fast_storage => for storing dynamic data
* stdext::packed_storage => same but with less memory
* stdext::packed_vector => std::vector with less memory
Compiling should be a little faster now because global boost including
is not needed anymore
* Add cotire cmake module to speedup compilation https://github.com/sakra/cotire
* Fix clang error and warnings
* Rename Font to BitmapFont to fix conflict with Xlib.g Font typedef
* Remove legacy PCH support
* Improve Position hash
Eduardo Bart