implement calendarWeeks option
it prepends a .cw cell to each row and displays the current calendar week before the first day of the week
defaults weekStart to monday
specs and basic styling included
Use better algorithm for calendarWeeks, don't use calendarWeeks in weekStart's definition
Adjust today button width when calendarWeeks is set
Tweak calendar weeks styles
Use standard option-extraction code for calendarWeeks option
Document calendarWeeks option
Update js/bootstrap-datepicker.js

If programmers use the class 'datepicker' to select the elements that should have the datepicker, then under certain conditions the datepicker opens up multiple times. This patch should fix that.
Only run hide function if picker is visible

Fixes #310
Date formate can now be set in the locals file.

The Date Formate is now related to the language.
Merge remote-tracking branch 'upstream/master'