Porting Tarrasch to GNU/Linux and other Unix-like OSes.

Series of patches to make Tarrasch work on Unix systems other than OS X. Mostly minor modifications to the code, and several makefiles.

Initial screenshot:
![2014-02-15-183835_2944x1080_scrot](https://f.cloud.github.com/assets/3255136/2179419/06c12362-96af-11e3-9680-9a346a056c8c.png)