several changes, made togglemax extern and separated it from zoom() - moved zoom...

several changes, made togglemax extern and separated it from zoom() - moved zoom() and togglemax() into layout.c, changed void (*func)(Arg *) into void (*func)(Arg), changed default keybindings of focusnext/focusprev and incmasterw to h/j/k/l accordingly, made keys in config*h appear alphabetically (special keys first), renamed resizemaster into incmasterw, renamed MASTER into MASTERWIDTH