This patch introduces:

 - A page that displays the documentation in a framed view.  The left
   side will show a full module index.  Clicking a module name will
   show it in the right frame.  If Javascript is enabled, the left
   side is split again to show the modules at the top and a very short
   synopsis for the module currently displayed on the right.

 - Code to generate the mini-synopsis for each module and the mini
   module index ("index-frames.html").

 - CSS rules for the mini-synopsis.

 - A very small amount of javascript to update the mini-synopsis (but
   only if inside a frame.)

Some perhaps controversial things:

 - Sharing code was very difficult, so there is a small amount of code
   duplication.

 - The amount of generated pages has been doubled, since every module
   now also gets a mini-synopsis.  The overhead should not be too
   much, but I haven't checked.  Alternatively, the mini-synopsis
   could also be generated using Javascript if we properly annotate
   the actual synopsis.