idmclib developers guide now online

After some delay, I've finally put online the html version of the idmclib developers guide.
The idmclib manual is already shipped with the idmclib, and can be compiled in html and pdf format. However, potential users which might want to just give a brief look to what idmclib is can now look at the developers guide without ever downloading the source package.

Note that the published guide is relative to the latest release of the library. I will try to keep it up-to-date with future releases. However, for older/newer versions, one can always look at the distributed idmclib packages.