ISIS-680: implement simple clipboard as replacement for zclip (flash)

Also:
- rebind bookmarked pages sliding panel's key to alt+[ (instead of alt+])
- bind the simple clipboard modal window popup to be alt+]

Also:
- move bookmarked panel tab to be in a more unobstructive place
- bind esc key to quickly close the bookmarked pages sliding panel
ISIS-680: remove the zclip (flash) stuff completely