Datepicker today option is enabled if today's date is outside of max-date/min-date range

[JamesM123]

The button to select Today in the datepicker is enabled and works even if today's date is outside of the valid max-date/min-date range.

I would imagine that if today's date falls outside the valid range of dates, then the today button should be hidden or disabled.

[wesleycho]

Given that the min-date and max-date are observable, this should likely use either ng-show/ng-hide or ng-if. I would imagine that the max-date and min-date would change relatively infrequently, so I think an ng-if would be ok.

[wesleycho]

Hmm, thinking about this more, I think a disabled would be more appropriate, perhaps with ng-disabled - this shouldn't be a difficult feature to implement if you want to open a PR.

[wesleycho]

Please do not do a +1, it does not offer any useful signal.