only fill calendar on first rendering

before we had some strange "hopping" behaviour when scrolling
ikhal: pressing `t` refocuses on today

this should fix #32 on github
removed debug option from config file, had no effect anyway

this should close #117 on github
zsh file completion minimal update

-V doesn't exist anymore

also should fix #71 on github
ctrl-w should delete words in ikhal's edit fields

should fix github #116