Added the ability to edit an assetstore.  I still need to put a warning message in place when there are files in the asset store and to remove some debug code, plus add tests.
Added a warning message if the assetstore has any files.
Added some assetstore tests to test assetstore edits.
Added tests for assetstore edits.  Removed all explicit timed waits in the web client tests and swicthed to actually waiting for appropriate actions.
Much like the GridFS assetstores, we weren't clearing the filesystem assetstores before running tests.  This was gradually using up disk space, but, more importantly, also meant the tests weren't as clean as they should have been.
Changed the parameter 'secretKey' to 'secret' in all locations for consistency.  Refactored a javscript `for..in` to use `_.each`.
Remove the subclass save function I had added to the assetstore model.  It is no longer necessary.
Merge branch 'master' into assetstore-edit
Populate the assetstore edit dialog before it finishes sliding in.
Merge pull request #418 from girder/assetstore-edit

Edit Assetstores