Adds global error handling to synctoolui.  It will work for most types of errors
except for errors that occur after the response has been committed: ie. namely jsp rendering errors.
However all other kinds of errors should be handled. The error page offers a little humor to help
soften the blow of failure and a button that enables them to send an email to support with the stacktrace (where applicable)
and a comment if they wish to customize the email.  This functionality can be simulated by typing in a random url into the
address bar (such as /sync/blah).  That will generate a 404 error.  To generate a controller based application error
hit /sync/test-error.  Notice the toggleable details button.
Updates .gitignore to re-add some items that were removed yesterday.
Removes the synctoolui email link (due to inconsistencies across browsers, operating systems, and mail clients). Replaces it with a button that returns you to the status page.