Disable tabbing of tree nodes (tabindex=-1).

If Prev/Next navigation is used, then ensure focus is retained after node is loaded and new toolbar is rendered (to retain keyboard context).
Allow plugins to provide Gemfiles
Move plugin gem loading into ASUtils
Add a new script for installing gems for a given plugin
Set plugin gem paths when first initialising gems
Copy plugins to Tomcat when configuring
Incorporate Mark Cooper's New Relic changes as a plugin
WIP add suppression test spec and begin moving things in there
Add suppressed to archival records
Suppression of tree record applies change to branch
Split suppression specs into model and controller tests
Add 'suppressed' column to all relationship tables.
Suppress relationships when a linked record is suppressed
Add suppress button, action and messages to frontend archival records
Add a function to all ASModel types to allow them to produce an object graph of all related/dependent objects.

Use this to implement suppression, suppressing entire object graphs in relatively few UPDATE commands.
Switch published to use the same object graph code as suppression.
Fix transient Selenium bug
WIP: deletion
First shot at turning external IDs into regular nested records
WIP get external id tests passing and only include ExternalIDs module once