Update wip/vimb to 2.1.

Changes:
- some gui style fixes for the build against gtk3
- change in the responsibilities of the c code and the JavaScript code for the
  hinting
- run hint script as anonymous object to avoid naming collision with opened
  pages
- extended hintmode that keeps the hints open until <Esc> is pressed
- added validation for setting of prev- nextpattern
- checkbox and radio-button state is shown in the hint labels