fix for bug rendering text at small sizes, padding was incorrectly being applied to the characters y offset causing out of bounds pixels to be requested from glTexSubImage2D().
also clamp width, height of the character bitmap to the bitmap bounds since this can still happen for very small text (2-3 pixels high).


git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk/blender@53533 954f8c5b-7b00-dc11-b283-0030488c597c