This change allows our permissions system to function.  We currently do not
want editors to have access to settings tab but we need them to be able to
change the layout and content.  This fixes an issue where when we have the
above need, the Panelizer tab is not displaying because it defaults to
settings which is the least used and (in our case) least desirable Panelizer
page to land on since our editors most often want to modify the content
placement.

Issue #1412022: Field API loses data on submit, causing panelizer to try to insert records it already has.

Issue #1414740 by twistor: Failure to include taxonomy term task leads to 500 error with term panelizer.

Generalize the panelizer task handler so that it can be added to custom pages as a handler. This can be used to create path trees to display panelized entities that are related via references or other relationships.

Issue #1406836: Using panelize with no default/choice caused Panelizer tab to not appear despite having permission.

Issue #1387634: Allow features to be able to see the default panelizer panel after it has been modified by the user.

This is so that we can use default selection when we build our node
forms through the page manager with variants.

Issue #1361648 by OnkelTem: Ensure comment module exists before adding comment panes to the default node panelizer panel.

Issue #1361620: Saving a panelized panel that was using a default panel could modify the default panel display.

Issue #1360948: Has no default, no choice should not show tabs for default panel configuration in admin pages.

Issue #1343480: custom CSS on a panelizer page should be added as part of the theme layer to have highest priority.

Issue #1329280: Add an "object default" to the css so that ctools export gives it a default properly.

Add panelizer paths to admin paths and fix panelizer task handler to work properly for default panelizer panels.