Using Font generator instead of font atlas

Some of the problems in widgets layouts where due to the font we were using. Instead of using a prerendered font, I added a libgdx utility to generate fonts on-the-fly (which is really cool and works far better than the other approach).

Also, I extended skin to allow loading .ttf fonts. All other changes are to undo all changes made to fix the layout in labels, textarea and textfields.