Adding travis-ci integration.
Changing format of travis-ci pre-install commands
Changing sdl2 dependency to libsdl2
Changing makefile to try to attempt to support the travis-ci servers
Adding libsdl2-dev dependency to .travis.yml
Made Makefile respond properly to UnitTest++.a not being present on the first build
Merge branch 'master' of https://github.com/Databean/warsofcatan into settlements_and_cities