Ignore artifacts from buildout and eclipse

And a local buildout configuration.
Refactor doctest setup

To actually use plone.app.testing layers
Typo on permission name

It was working before because all tests (and probably all production installations) used the "Manager" role, and this role shortcuts the permission evaluation, even when the permission doesn't exist.
Minor logging refactor
Refactor permission check
Unused variable
Fix thread count (issue #6 from github)

Fix `zopethreads` view based on `Products.ZServerViews`.

At the same time, fix the algorithm for calculating free and total threads using actual information form ZRendevous instead of relying on heuristics.
Documentation about `zopethreads` and bump version