allow ajax data parameter to be specified as a function

(test updated by arshaw after-the-fact)
cleanup data_as_a_function code
future/past classNames on day cells
don't throw error if event's title is blank or null
Add option to not automatically hook window.resize
hookWindowResize -> handleWindowResize
use jQuery to detect if body/calendar-element is visible and ready for rendering
fix bug with agenda event grid snapping, landing on wrong day (from PR#55)
eventStartEditable/startEditable AND eventDurationEditable/durationEditable
put event z-index's into stylesheet
small performance-fix for minute-scaled slots
refactor and simplify the way view switching/rerendering works
new callbacks: viewRender, viewDestroy
new callback: eventDestroy
test file for new callbacks
fix bug with public render method. a few tweaks
call destroy callbacks when the calendar's destroy method is called. misc
jQuery UI 1.10.3
jQuery 1.10.2
update tabs test for latest jQuery UI