BGE: Fix for precision lost in setBackground/getBackground at Video Texture

Now internally the variables are processed as floats avoiding int->float->char conversions that are causing precision lost.

A check for int numbers is maintained to keep compatibility with old behaviour.

Reviewers: ben2610, campbellbarton, moguri, hg1

Reviewed By: moguri, hg1

Subscribers: campbellbarton

Projects: #game_engine

Differential Revision: https://developer.blender.org/D1301

doc/python_api/rst/bge.texture.rst

@@ -218,6 +218,8 @@ When the texture object is deleted, the new texture is deleted and the old textu
 
       background color
 
+      :type: int or float list [r, g, b, a] in [0.0, 255.0]
+
    .. attribute:: capsize
 
       size of render area
@@ -315,6 +317,8 @@ When the texture object is deleted, the new texture is deleted and the old textu
 
       background color
 
+      :type: int or float list [r, g, b, a] in [0.0, 255.0]
+
    .. attribute:: capsize
 
       size of render area