Removed prerendered text images.

Removed prerendered text images from everywhere, so now user interface is properly scaled to full screen mode and can be easily translated. You will need "Box.png" in common.dat/image.
![box](https://cloud.githubusercontent.com/assets/8434495/4277434/d55e54f0-3d0e-11e4-9c97-4b0f0d351156.png)

Also some fixes with text outlining. Added alternative outlining method through `TTF_SetFontOutline` function as described [here](https://forums.libsdl.org/viewtopic.php?p=22030&sid=73ef7e16d0fb30f042314ee41cc89304#22030). It have better quality than "manual" method because antialiasing, but it have some strange artifacts, from which I could not get rid of. Here is example:
![sdl outlining](https://cloud.githubusercontent.com/assets/8434495/4277500/a10cd19e-3d0f-11e4-9b24-7e5589f61038.png)
Pay attention to the wrong "shadow" of some chars (n, u, o, k).
I hope to fix this in the future, so I left implementation in code.