Retain user preferences on document embed dialog

Fix for issue #41.  Discovered that the preferences key was specified
incorrectly and the 'Link to original PDF' check-box wasn't being
restored.
Lets ignore the data directory, rather than the full solr app.
COMMIT ALL THE THINGS (well all the solr4 related things). To be sorted through more carefully later.
Merge branch 'master' into solr4
Setting up test solr4 instance.
Conceptual failure in invocation of image copying.
Go with solr schema from the sunspot wiki.
Merge branch 'master' of https://github.com/documentcloud/documentcloud
Setup for reindexing all documents.
Missed two actions on the reindexing nodes.
Commit document changes manually and raise Solr autoCommit time.

When testing the new solr4 branch, newly uploaded documents where not
appearing in search until after solr was restarted.

This was because commit was not being called on the index.  autoCommit
was enabled, but the openSearcher option wasn't.

This extends the run interval for autoCommit to 10 minutes, and
enables autoSoftCommit every 5 minutes.  It also calls commit manually
on the index after a document is inserted or updated.

Documents will appear in the search immediately after uploading and
the somewhat expensive commit will be called less often.
Upgrade sunspot_solr to the latest pre-release version

This version incorporates a fix for the sunspot:solr:stop rake task
failing to terminate the Java process.  The previous version was
over-escaping the sunspot:solr:start command, causing a sub-process
to be created and incorrect PID logged.  The change we need is
discussed at: https://github.com/sunspot/sunspot/pull/221
Merge branch 'master' of https://github.com/documentcloud/documentcloud
Merge branch 'master' of https://github.com/documentcloud/documentcloud
Merge branch 'memberships' of https://github.com/documentcloud/documentcloud
Add third-party login icons to sidebar on home page
new AMI id.
Express node shouldn't be reindexing either.
Splitting search server behavior from central server behaviors.
Reenable all actions for the solr4 branch