Only syntax errors

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

Introduce a new dependencie between lodelContext & multisite plugin

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

Warning, may contains some bugs !!!

Deleting code from old standalone server

Seems to works !! :)

+ bugfixes in show_object_detailled

forget to name the argument

Now when we try to update an object that do not exists a 404 is answered and not a 500 anymore

Now we are able to limit the number of spawned child processes

Now listening address, listening port and max_children count can be configured using the Settings module

Adding a cache for app module reducing seriously routing overhead

Now all "empty" values are deleted from the resulting array

There were manual import through importlib, we have to replace them with LodelContext calls.
Actually the plugins module is in a dirty state....

Replace some old pure python import by LodelContext calls
Change the plugins imports methods to use LodelContext instead
Fixes dyncode exposure method

Implements a new exception class for webui : HttpErrors that uses a new template : errors.html to display multiples errors