Android, libtcod & gesture support

I've the beginnings of a gesture experimentation prototype running on Android within the libtcod sample program.  Currently it just allows the authoring of a gesture, but it's fairly straightforward from there to have the user author several gestures, then draw something and see which gesture SDL detects that it should be.

The SDL 2.0 gesture support works wonderfully.  But unfortunately a little too wonderfully, even unknown gestures are matched and the aspect that would distinguish a bad match, seems to be broken.  Currently every matched gesture has an error of -2.0.  Something I apparently have to debug myself, using printf-based debugging as proper debugging does not work at the C level.

More to come..