[server] extract "no pooler" CnxSet class to a _BaseCnxSet class
So we get rid of "if self._queue is None" in each method of _CnxSetPool
Also add helper get_cnxset(source, size) to instantiate the correct pooler class.
Edition control
===============
This chapter covers the editing capabilities of |cubicweb|. It
explains html Form construction, the Edit Controller and their
interactions.
.. toctree::
:maxdepth: 2
form
dissection
editcontroller
examples