DatePicker property week-starts-with

[frohikey]

I know you've assigned yourself to #54 but I needed it very fast. So I did implement it and updated Docs.

Changes proposed in this pull request:

• Added week-starts-with property to DatePicker. I've decided to use more universal approach and defined it as Numeric property.

@wxsms

[coveralls]

Coverage increased (+0.06%) to 95.127% when pulling a3ead26 on frohikey:week-starts-with into b5b9e06 on wxsms:master.

[wxsms]

Thanks.
But, Have you found that your implementation is not good enough? Datepicker lose few starting dates sometimes.