New datetimepicker

Addresses #1717, #1675

Adds a new datetimepicker to the manual entry and edit pages.  The datetimepicker allows for times between 1-1-100000, BC and 12-31-100000, AD.  It's pretty fast (the slowest operation takes maybe 5ms on chrome?), and has incredibly primitive tests.  Also, it supports all (or most, not 100% sure) of the date formats used by iSENSE.  I know I covered unix timestamps, ISO, and yyyy/mm/dd hh:mm:ss.

I just kind of threw the datetimepicker on the page.  Ideally there would be a button you click and stuff, but apparently the current edit form is being tossed in favor of something using slickgrid, so you just click the textbox to open the picker and click it again or anywhere else to close it.