feat(calendar): emit an event when View is changed

[liviuciulinaru]

I have added a new event to know when the view of the calendar is changed (eg. user has changed the month). I am building a complex booking system and I need to calculate the disabled dates based on the current view (eg. when the user changes the month, a request to the server is made to get the disable dates).

The event object will contain the activeDate and the datepickerMode.

[codecov-io]

Codecov Report

Merging #1703 into development will not change coverage.
The diff coverage is n/a.

@@             Coverage Diff              @@
##           development    #1703   +/-   ##
============================================
  Coverage        85.44%   85.44%           
============================================
  Files               85       85           
  Lines             2295     2295           
  Branches           300      300           
============================================
  Hits              1961     1961           
  Misses             235      235           
  Partials            99       99

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 27a0229...3aa7743. Read the comment docs.

[valorkin]

Thanks!