Plone.app.viewletmanager

------------------

- Do not catch conflict errors and keywordinterrupt in viewlet manager.
We can programmatically setup the exceptions that are not caught.
[thomasdesvenain]

- If render fails, be more verbose about the exception to know where and how it
happens in the stack. [kiorky]

- refactor JS in template.
[petschki]

------------------

- Handle exception during viewlet rendering process: log the exception and
display an error message. [toutpt]

------------------

- Hiding viewlets for ``skinname="*"`` was not working properly.
Closes http://dev.plone.org/plone/ticket/10903
[garbas, WouterVH]

- Add ``plone.app.vocabularies`` as dependency to get the list of existing skins.
[WouterVH]

- Add MANIFEST.in.
[WouterVH]

------------------

- Depend on ``Products.CMFPlone`` instead of ``Plone``.
[elro]

- Explicitly unregister IViewletSettingsStorage utility to prevent test bleed.
[esteele, cah190]

------------------

- Update license to GPL version 2 only.
[hannosch]

----------------

- Silence `Nothing to import / export.` log messages.
[hannosch]