don't miss brief button clicks or other inputs

mouse clicks, scroll motions, key presses, and joystick motions that are
activated then de-activated very quickly are now active for at least one
logical frame, so that they are not missed.

Fixes #1048
Merge pull request #1054 from dorkster/fixes

Check for undefined tiles when validating map tiles
Merge pull request #1052 from sudoman/fixes

don't miss brief button clicks or other inputs