Make tree fragment's expandable current view expand by default

This gives the user a clearer overview of the current state of the
application, without having to expand all the tasks.

Padding has been reduced to better utilize available screen space.

The bring to front and remove buttons are currently always hidden.

Test: Manual
Change-Id: Ifcda0ff31fd5adb89a12ff6a024842c0e7a7ab29