Fix the bug that causes crashes on plugin unloading.

Fix old Xkb handling code. The original code, that could do some of the things listed below, has been ripped out.

Make sure to restore the keysyms for keys we've configured when exiting. Then we can potentially bind any key to any set of commands.
(i.e. we can add a macro EAK_EMITKEYS(x,y,z) to emit keycodes for keys x, y and z. However, were we to do this now, once
we exit lineakd, that key would cease to function.

Assign real symbols to each and every key. Currently, when mapped, we have a valid keysym and keycode, but no actual symbol.
A real symbol should allow us to not bind a key to a command, but also use it in keybindings w/ other programs, like in KDE or
GNOME.

ADD modifiers to the config file and parser.
Modify the main event loop to look for modifiers and keys as well as buttons.
Make lkey a subclass of lobject. Make lbutton a new subclass too.
