Improved message template checking.
* If no changes have been made to the message template the check is local only and trivial.
* If changes have been made to the message template then compatibility is verified on the first build after the change instead of when they package.
* Automated systems can use --force to force full message template verification

* Built the viewer and verified only the hash is checked.
* Changed the template and verified full verification happens and a new sha1 saved.