WIP: adding padding around glyphs to allow for 3d-text with mip-mapping.

* font image includes padding.
* full padded image is subloaded into texture
* TODO: glyph packing does not fully take padding into account (?)
* TODO: quads do not take padding into account, text is offset to the right, instead of flush.
Merge branch 'master' into feature/padding
Fix: quads did not take padding into account

text was offset to the right and down instead of flush.
test: made font bigger
Merge branch 'feature/padding'