Fixes:
- Properly parse date string, fixes #735 #755 #688
- Cleaner packages, see #542 #580
- Add space for XHTML, fixes #526
- CSS fixes, see #431 #430 #809 #883 #237 #869 #869 #730
- Add clear functionality, see #720
- Use unique IDs, fixes #650
- Bubble event on left arrow, fixes #710
- Show week numbers based on ISO 8601 by default, fixes #388 #825