init page after lowerLimit when opening picker

[aperron]

When opening the DatePicker the lowerLimit date is not taken into account to init pageDate. So there can be no selectable date on the first page.

I can also add a new prop to activate this behavior if it's better.

Thanks for your great job.

[winterpk]

This looks good. I need this fix for my project.

[icehaunter]

Thanks for the PR! Sorry for a very long merge time. I slightly edited your code, but it's merged :)