Imio.actionspanel

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

- Moved complete computation of back url when an object is removed to
_computeBackURL, not only the case when we were on the object we just removed.
- Added CSS class `actionspanel-no-style-table` on the main actions_panel table
and defined styles for it to remove any border/margin/padding.

----------------
- Added section that render a link to the object's history if useIcons is True
- Not triggerable transitions are now also displayed using icon if useIcons is True,
before, not triggerable transitions were always displayed as button, no mater useIcons
was True or False
- Simplified method that compute addable contents, the default `folder_factories`
does all the job
- Manage the fact that if after a transition has been triggered on an object,
this object is not accessible anymore to the current user, it is redirected
to a viewable place

----------------
- Do not lookup an object UID in the uid_catalog,
this fails when using dexterity, use portal_catalog or
check context UID if element is not indexed
- Do not display a `-` when no actions to display and not using icons
- Implement `__call__` instead of `render` on the actions panel view
so calling the view is simpler
- Display AddContent actions.

----------------
- Optimized to be `listing-aware` do some caching by storing not changing parameters
into the request and so avoid to recompute it each time the view is instanciated
- Corrected bug when a transition was triggered using the confirmation popup and
resulting object was no more accessible, the popup was recomputed and it raised Unauthorized

----------------
- Initial release