Input Mapping Tables are still at the core as they are a good concept,
however they include both axis and button mappings, and the size is not
hard-coded, but dependent on the known devices. Not much actually works
yet (nq segfaults when a key is pressed).
The recent changes to key handling broke using escape to get out of the
console (escape would toggle between console and menu). Thus take care
of the menu (escape) part of the coupling FIXME by implementing a
callback for the escape key (and removing key_togglemenu) and sorting
out the escape key handling in console. Seems to work nicely
This refactors (as such) keys.c so that it no longer depends on console
or gib, and pulls keys out of video targets. The eventual plan is to
move all high-level general input handling into libQFinput, and probably
low-level (eg, /dev/input handling for joysticks etc on Linux).
Fixes#8
