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
Create a new shared pointer type stdext::shared_object_ptr and stdext::shared_obj
using boost::intrusive_ptr
Advantages:
* half memory usage
* faster and lightweight
Disadvantages:
* using weak_ptr is not supported anymore
* compiling seems slower
* Fix recursive reference memory leak in UIWidget
* Make Event/ScheduledEvent memory-leak safe
* Fix exit crashs by freeing graphics resources before destroying GL context
* Add many asserts to avoid any leak regression
* 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