WIP SDL2 branch.
Directory rename
Updates to get the game running under SDL2.
Updated project VS files.
Fixed the bug with missing textures and the debug console/text input not working.
Milgram Block footsteps

The Milgram Block now has footstep sounds!
(cherry picked from commit 3302404589c88667ecae456dbf81637a9e707c2c)
More updates, compiles/runs on windows using SDL-1.2 and SDL2. Linux compiles with SDL2/SDL-1.2 but doesn't run on my test. Linux clipboard needs to be fixed.
Added bar_widget for making bars with tick marks.
Merge branch 'master' into SDL2
VS project file.
Merge branch 'SDL2'