Added jsp's for managing sponsors and made corresponding changes in the
controller servlet.
Ensure that each instance of entity manager is properly closed.
Switched to using @Webservlet annotation instead of servlet entry in
web.xml.
Fix to reference to "update-greyhound" page.
Implemented ability to upload an image of a greyhound that is stored in
db.
Removed unused import.
Merge remote-tracking branch 'origin/master' into Sponsorship