Documentation is .mobi format

[Geert Janssens]

Some time ago SASAKI Suguru contributed some code to generate epub and 
mobipocket formatted files for our documentation. The ebup format was 
activated fairly soon thereafter on the unstable documentation nightly 
builds, but there were some issues with the mobi format at the time.

These issues have now been resolved. As of this morning you can now 
download both epub and mobi formatted files for the unstable 
documentation from our website.

With the next documentation release (due very soon now), this will also 
appear for the stable documentation.

Stay tuned... ;)

Geert