Add full version string

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>

app.js

@@ -178,6 +178,7 @@ app.set('view engine', 'ejs')
 // set generally available variables for all views
 app.locals.useCDN = config.useCDN
 app.locals.serverURL = config.serverURL
+app.locals.sourceURL = config.sourceURL
 app.locals.allowAnonymous = config.allowAnonymous
 app.locals.allowAnonymousEdits = config.allowAnonymousEdits
 app.locals.allowPDFExport = config.allowPDFExport