- add some files extensions to doxyfile (*.am *.in *.ac *.patch)
- add a documentation page on autotools usage

Commit refs #122 and fixes #133

- webui now calls a hook to indicate a session end
- loader.py now set a lodel.dyncode module exposing dynmically generated code

- renamed Plugins class to Plugin
- an instance represent a loaded plugin
- classmethod allows to preload & load plugins

Adding images support for doxygen documentation ( in doc/img ) + automated images generation with graphviz & make

Now we have a main page on doxygen