Travis yml

I've gotten to the point where I can generate a makefile and start a build, which is good, and required a lot of work, and maybe we are close to the finish line. Maybe.

- FindPkgConfig completely failed to find sdl2 package which was in an obvious place (/usr/include/sdl2) I had to hardcode it in to get the build to continue. Some way of modularizing this would be good

- I then ran into the error here: https://travis-ci.org/kevinburke/OpenRCT2/builds/25922388 which I have no idea how to fix or what I'm doing so I'm going to stop and ask for help.

```
/usr/include/bits/time.h:31:8: error: redefinition of ‘struct timeval’
/usr/lib/gcc/i686-w64-mingw32/4.6/../../../../i686-w64-mingw32/include/_timeval.h:10:8: note: originally defined here
In file included from /usr/include/sys/types.h:220:0,
                 from /usr/include/stdlib.h:320,
                 from /usr/lib/gcc/i686-w64-mingw32/4.6/../../../../i686-w64-mingw32/include/objbase.h:87,
                 from /usr/lib/gcc/i686-w64-mingw32/4.6/../../../../i686-w64-mingw32/include/ole2.h:16,
                 from /usr/lib/gcc/i686-w64-mingw32/4.6/../../../../i686-w64-mingw32/include/windows.h:94,
                 from /home/travis/build/kevinburke/OpenRCT2/src/gfx.c:25:
/usr/include/sys/select.h:76:5: error: conflicting types for ‘fd_set’
/usr/lib/gcc/i686-w64-mingw32/4.6/../../../../i686-w64-mingw32/include/psdk_inc/_fd_types.h:19:3: note: previous declaration of ‘fd_set’ was here
/usr/include/sys/select.h:107:12: error: conflicting types for ‘select’
/usr/lib/gcc/i686-w64-mingw32/4.6/../../../../i686-w64-mingw32/include/winsock.h:317:34: note: previous declaration of ‘select’ was here
```

I had to include the "bits" directory because "features.h" was loading something from "bits/predefs.h". Maybe features.h should be loaded from some other place besides /usr/include.