review of Color class.

- alpha is handled in algebrical operations
- slightly different 'clamp' logic (unpack methods can be called with a
clamp flag and there's a new clamp() method)
Added prefedinet set of Named Colors

ColorNames namespace with a set of 147 predefined standard color taken
from http://www.w3.org/TR/SVG/types.html#ColorKeywords
Texture improvements

-Texture.fromTexture
- check for src classtype (must be a texture)
- correcly handles rotated flag
- returns a copy of the src texture if (0,0,1,1) not rotated region
-texture:copy()
-added _fillQuadUv / _fillQuadDeckUV methods (to centralize texure quad
logic)
-Texture:getWidth() / getHeight()
vec2:copy()
Fixed ldoc comments
DisplayObjTransofrm

Class definition that includes all gemetrical transformation infos about
a display obj. Can be set/get in a single call and it's usefull in order
to create animation objects
Updated documentation
missing includes for ColorNames and DisplayObjTransform