- various cleanup and split of code to make it more testable
- start writing some tests

This code is generic enough to be used by others libraries.

The code on ERP5TypeTestSuite is preserved for backward compatibility for
now, until it got updated.

Forgot to bump egg version.

Otherwise other directories may be considered as part of erp5.util
(such as product).

It is more consistent with existing naming within erp5.util and
zope.testbrowser parent module as well.