might want to tweak the hide show values later

This commit contains various fixes and enhancements, mostly because I
was too lazy to commit small changes.

* Add topBarCollapseOnScroll style property which compliments
  navBarHideOnScroll. This property is needed when showing a
  collapsing topTabs screen. In this case the developer might to keep
  the titleBar bar when the screen is collapsed.
* Reduce collapse sensitivity by taking scaled touch slop into account
* Cancel touches when collapsing. This fix prevents buttons from
  responding to touch events when collapse ends.

Add expendOnTopTabChange style property which defaults to true. Setting it to false

consider changing this later on

* update .gitignore added #VSCODE section

* added # VSCODE

* Add showInAppNotification autoDismissTimerSec param

* Default autoDismissTimerSec of notification to 5, like on iOS

* Add param to disable notification auto-dismiss behaviour.

* Update showInAppNotification example with optional params

* Add .hideInAppNotification on android.

- Separate hide and show animations.
- Implement a little bit of throttling around successive calls to .showInAppNotification

* Update example to demo dismiss.