Win32 build adjustments (includes a sdl2 contrib update).

This builds, but crashes on startup; I believe it has to do with the
sdl2 contrib using thread/generic. I'd like to use thread/stdcpp since
we are using C++11 now, but we need to figure out how to get that to
build first.
install sdl2 for travis
add a ppa that should hopefully include sdl2 packages
this ppa uses different package names
Travis: still install SDL1.2, so tile gen utils can use it.

Until we can get those ported over too.
Build contribs in the right order and link them in the right order.

This particular bit of code wizardry is making me loopy.
Be less loopy in the Makefile (gammafunk).
Poke SDL2 contrib for OS X fixes.
Use SDL2 for tilegen
Updates to sdl2 contrib
Revert "Travis: still install SDL1.2, so tile gen utils can use it."

Now that SDL2 is working for and used by tilegen, remove this since it
may interfere with the travis build.

This reverts commit c371c2d767e79df2fc687b535fbff1dcc79ac0ed.
OS X Makefile updates to add missing frameworks
Poke sdl2 contrib - Win32 now runs!

It interacts bizarrely with trying to enter in numbers, but it runs...
Use a more up-to-date ppa for SDL2 for travis.

Hopefully this will motivate trollvis to build this properly!
Don't produce hieroglyphics when trying to type in numbers.

Oops.