Deploying a snapshot will update the cache/version number

This PR creates a new version whenever we deploy a snapshot using the `make deployint SNAPSHOT=***`, `make deployprod SNAPSHOT=****` or `./scripts/deploysnapshot.sh int/prod ****` commands because that's usually what we want.

Note that we need to have the same version number on each instance of a given staging because otherwise, our offline/appcache mechanism will fail.

@procrastinatio Does this make sense?
Good point. I use always `make clean all`  which  rebuilds the js.