[forms] fix form_needs_multipart implementation problem ------- The current implementation of form_needs_multipart goes down recursively in all inlined forms to check if one of them needs a multipart enctype. If we have a relation definition as X part_of X, the previous implementation potentially lead to an infinite recursion

This directory contains extra libraries which are needed
to make cubicweb work.

The mx.DateTime python implementation is directly taken from
the mx.DateTime distribution. The only modification is the
strptime function which has been mocked using the standard
``datetime`` module. (as provided by the python2.5's stdlib)