Redrawing the screen is the most expansive operation, we don't want to
do it every time an event happens (imagine fast scrolling mouse wheel).
Also adding missing licences.
This can be a more viable option for some users as it is less resource
intensive. The user knows when the data in any of the widget changed and
thus can trigger a redraw. External events still redraw the terminal
immediately.
Done here:
- Added a controller for the manually triggered redraws.
- Added an example of using termdash with triggered redraw.
- Removing couple of races in the test by waiting for the event queue to
empty before comparing values and by moving the test of terminal resize
into the test that triggers redraws.
