Collective-eeafaceted-batchactions

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- Moved method `browser.views.brains_from_uids` to `utils`, added helper method
`utils.listify_uids` that turns the data uids that is a string with each UID
separated by a comma into a real python list.
[gbastien]
- Display number of elements affected by action in the batch action form description.
[gbastien]

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- Added weight attribute on batch action forms to order them.
[sgeulette]
- Improved brains_from_uids
[sgeulette]
- Added utils method
[sgeulette]

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- Don't apply changes if form errors
[sgeulette]

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- Moved js variables to `collective.eeafaceted.z3ctable`.
[gbastien]

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- Render batch action form in overlay by default, but otherwise with form 'overlay' attribute set to False.
[sgeulette]

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- Added condition on apply button.
[sgeulette]
- Added _update_widgets method
[sgeulette]