NzImage now handles mipmaps

Added NzRenderer::SetClearColor(const Color&)
Added describe comment for pixel formats
Fixed NzPixelFormat conversion for RGBA4 and RGB5A1 types
Fixed NzRenderer::Clear prototype
Renamed NzLock to NzLockGuard
ResourceLoader's loaders are now tested from newest to oldest

src/Nazara/Core/LockGuard.cpp

@@ -2,17 +2,17 @@
 // This file is part of the "Nazara Engine".
 // For conditions of distribution and use, see copyright notice in Config.hpp
 
-#include <Nazara/Core/Lock.hpp>
+#include <Nazara/Core/LockGuard.hpp>
 #include <Nazara/Core/Mutex.hpp>
 #include <Nazara/Core/Debug.hpp>
 
-NzLock::NzLock(NzMutex& mutex) :
+NzLockGuard::NzLockGuard(NzMutex& mutex) :
 m_mutex(mutex)
 {
 	m_mutex.Lock();
 }
 
-NzLock::~NzLock()
+NzLockGuard::~NzLockGuard()
 {
 	m_mutex.Unlock();
 }