Move everything from global namespace to "sp" namespace

When writing the X11 (linux) implementation there was a problem with X11 defining a "Display" type and we also have a Display class in the engine.

So to fix that problem and minimize the risk for running into other name conflicts. We move everything from global namespace.

source/Display/GLContext.cpp

@@ -3,11 +3,13 @@
 
 #ifdef _WIN32
 #include <Platform/Win32/Win32GLContext.h>
-typedef Win32GLContext ContextType;
+typedef sp::Win32GLContext ContextType;
 #else
 #error "No GLContext implementation exists"
 #endif
 
+namespace sp {
+
 GLContext* GLContext::create()
 {
 	return new ContextType();
@@ -17,3 +19,5 @@ GLContext::~GLContext()
 {
 	// Nothing to do.
 }
+
+} // namespace sp