Currently we only provide the version from `package.json`. This means
that during updates of instances, e.g. the demo instance, which runs
latest master instead of a stable release, changes are not reflected to
the webclient.

This patch adds a fullversion string that contains the current commit
and this way makes that clients are notified about changes.

Signed-off-by: Sheogorath <sheogorath@shivering-isles.com>