Guard some functions against non valid BitmapData
Guard against some possible null values.
Fix for documentation generation
Don't let a negative width / height to be passed
Merge branch 'bitmapdata_isValid_fixes' into ogl_bitmapdata_draw
Fix colorMask(). BitmapData.draw() needs every color and alpha enabled
while the application can have the alpha disabled making the
BitmapData.draw() to fail. Also fixed some places where the colorMask()
had everything enabled skipping the application configuration.