Rewritted ResourceLoader and moved it to core

Added creation constructor to NzImage
Added member function functor
Added option to build Nazara as one library (instead of many)
Fixed some 2011 copyrights
Made use of "using def = T" C++11 feature instead of some illigible
typedefs
Removed unused premake file

include/Nazara/Utility/Enums.hpp

@@ -127,7 +127,7 @@ enum nzImageType
 
 enum nzPixelFormat
 {
-	nzPixelFormat_Undefined,
+	nzPixelFormat_Undefined = -1,
 
 	nzPixelFormat_BGR8,    // 3*nzUInt8
 	nzPixelFormat_BGRA8,   // 4*nzUInt8