Only syntax errors

Implements dyncode update for handled sites in lodelsites. solves #260

Now we are able to control EditorialModel load process at runtime
for lodelsites handled sites dyncode generation

Introduce a new dependencie between lodelContext & multisite plugin

Now the context manager handles lodelsites paths

Thoses modification has two goals :
- make lodelcontext fit with the new FS organisation implemented by the
lodelsites datasource
- make the dyncode exposure more "flexible"

Note : no solution implemented for MONOSITE

Associated to multisite loading & context stuff. I choose to commit this
change in master because it is important to not break the fact that
the buildconf HAS TO be importable safely outside any context.

At this point the loader in lodel/plugins/multisite/run.py is theorically
complete & correct. But some features are missing in order to be able
to test & debug it ( refs #275 ).

Now we are able to insert a lodelsite

no debug has been made on those piece of code

As a primary_key field has to be unique, added a check at DataHandler
instanciation to make sure a field set as a pk is not set as non-unique

Warning, may contains some bugs !!!

For the moment there is only uninstalling by name that works because #207

Clean take care of deleting plugins with same name and different versions
(the lower versions will be deleted)

Now in verbose mode we are printing all plugins, even those with duplicated
names and different versions