restyle calendar with fixed layout
improve fixed controls layout
implement popup for existing events
implement popup for new event
add default values to new event input
implement edit event popup
improve timetable.js performance

Now approximately 2.5 times faster!
For a group of 4, loading a busy next week takes 230ms as compared to 500+ms before.

Also modified popup labels.
improve popup control

Now with popupStatuses.HIDDEN, .READ_ONLY and .EDITABLE.
relayout header