Move, instead of deleting the snippet if it fails the syntax check.

Instead of outright deleting the file, it is moved to .broken. This
facilitates debugging as the file is left lying around without disturbing
sudo (dot in the filename).

To clean up, the file is removed before the syntax check. This leaves the
.broken file around until it passes the syntax check.
Merge pull request #10 from DavidS/master

Move, instead of deleting the snippet if it fails the syntax check