v3.1.0

Changes:

Fixes:
* #389 top orientation not accurate 
* #476 Always fire dp.change event when value changes from invalid state

Enchancements:
* #130 thanks @csnauwaert a new option `calendarWeeks` now allows showing weeknumbers in day view
* updated 24hour detection to look for hh/HH besides a if format string thanks @caponica
* Added grunt task to build nuget package