Alphabetical commit
Improved MemoryPool class

It's size is now dynamic (defaulted to 1024)
Added MemoryPool::GetFreeBlocks()
Added MemoryPool::GetSize()
Tried to make it thread-safe
It supports dynamics allocations (in case where it can't allocate memory
from the pool for some reasons)
Fixed some of the pull request code in order to merge it
Added Gawaboumga to the "Thanks to" list
Updated OpenGL headers
Commited missing file (from 7dfb82)