Catch all exceptions in our handlers, not just StandardError subclasses.

This matches the behaviour of ActionDispatch::ShowExceptions. Some
Ruby developers (like this one, until very recently) aren't aware that
you should subclass StandardError, not Exception, when creating custom
exception classes. Such exceptions would thus not be reported to Rollbar.
Merge pull request #100 from bikeexchange/FixExceptionCatch

Catch all exceptions in our handlers, not just StandardError subclasses.