Allow default tab + hiding of switch tab buttons

[aychtang]

Allows you to select an initial tab in case you want to go straight to the time picker, also allows hiding of tabs to ensure users stay on the given tab.

Code available on my fork @ https://github.com/trayio/input-moment.

Let me know if you want me to make a PR for either feature and I will split them and write tests.

[wangzuo]

Sure, pr is welcome.

[aychtang]

OK, have been quite busy recently but will do this soon.

[aychtang]

OK I have added these features in #78 & #79 respectively.