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/Math/Color.cpp

@@ -1,6 +1,8 @@
 
 #include <Spectre/Math/Color.h>
 
+namespace sp {
+
 const Color Color::Black	(0  , 0  , 0  , 255);
 const Color Color::White	(255, 255, 255, 255);
 const Color Color::Red		(255, 0  , 0  , 255);
@@ -126,3 +128,5 @@ Color operator *(const Color& c, unsigned int s)
 {
 	return Color(c.r * s, c.g * s, c.b * s, c.a * s);
 }
+
+} // namespace sp