Initial first day of the week commit

+ Added option to change the first day of the week, currently only
supports numerical value of day (0 = Sunday, 1 = Monday, etc.)
First day of week now option compliant

+ Now fully uses the option setup already in place
+ The firstDayOfWeek option can be stored in the picker's data object
Revert "First day of week now option compliant"

This reverts commit 9a2ab4aafc029237f2b11f7a7d7f465d3eb4f7d3.
First day of week option now can be called using data object

+ Now fully uses the option setup already in place
+ The firstDayOfWeek option can be stored in the picker's data object
Merge branch 'pr_36' into 1.3.x

Conflicts:
	jquery.simple-dtpicker.js