Big cleanup of tooltip code
Big cleanup of tooltip code

* create tooltips on demand instead of at initialisation. This reduces
  DOM cluttering.
* show AJAX tooltips immediately with a <progress/> element, dropping
  in content and repositioning after load. fixes #12
* close tooltips on click on tooltip, except for sticky tooltips.
  Fixes #10.

janga1997/Patterns,garbas/Patterns,janga1997/Patterns,janga1997/Patterns,garbas/Patterns,garbas/Patterns