First part of render texture commit

Added NzContext::EnsureContext and NzContext::GetThreadContext
Added NzCube
Added NzRect::GetCenter
Added methods to send vectors to shaders
Added NzRenderer::SetViewport
Fixed NzRect::ExtendTo calculations
Fixed NzImage::Update checks with level > 0
No longer use glTexStorage when creating a texture to prevent a bug
NzBuffer's Lock and Unlock operations renamed to Map and Unmap
NzVector2/3/4 can now cast implicitly to a pointer
Optimized compilation time of String.hpp
Optimized normalisaton of quaternions
Optimized passing uniforms to shaders
Quaternion now automaticaly Normalize h
Removed macro definition of NAZARA_RENDERER_OPENGL from Renderer
Removed implicit cast from NzVector2/3/4 to NzString
Renamed nzBufferLock to nzBufferAccess
Renamed NzRenderTarget::CanActivate to IsValid

src/Nazara/Core/Win32/ThreadImpl.cpp

@@ -67,7 +67,7 @@ void NzThreadImpl::Terminate()
 
 unsigned int _stdcall NzThreadImpl::ThreadProc(void* userdata)
 {
-	NzThread* owner = static_cast<NzThread*>(userdata);
+	NzThread* owner = reinterpret_cast<NzThread*>(userdata);
 	NzFunctor* func = owner->m_func;
 	HANDLE myHandle = owner->m_impl->m_thread;
 	func->Run();