visibility: use F1-6 keys instead

numbers should only be used for repeating commands...
move_relative: fix wrt. hidden calendars
not sure if this is the right approach
move_now: always deselect so we don't get stuck

fixes an annoying bug when trying to move when selecting something
t: don't center view automatically

sometimes you just want to jump to now without messing with your view.
Maybe we should still center_view when we're not in the range at all.
pushmove down with C-j
zoom in more by default
fix crash in push_down
ui: redraw every 500ms
misc: fix some warnings
dont crash on alignment for now
fix hour placement issue
tab to switch calendars
anything rendering related should probably be localtime...