Initial classes for recording Dryad usage events
Add DRYAD_USAGE_FILE to log4j.properties
Add Usage logging to login form
Move EventLogger to Dryad Customized API

Change package to org.dspace.usagelogging
tidy up passwordlogin logging
Add usage logging to submission system
Merge pull request #476 from datadryad/trello-44-usagelogging

Initial implementation of usage logging