Feature - Change week day text gravity

[Mahmoood]

In the tiny added change user can change the text gravity of weekdays.

Currently, both weeks header and days headers have the same height and that makes a large spacing between the week's header and the first row of the calendar (weekly or monthly), to fix that user can change the gravity of the weeks' header to BOTTOM using:

widget.setWeekDayTextGravity(Gravity.BOTTOM);