Makes it possible to set empty password

Wraps user and password into double quotes to avoid variables with spaces to mess with the command line.
Also removes the colon from the password substitution to allow for empty passwords.
Only done for password, as empty user would possibly mess heavily with TiddlyWiki, as it uses the username to sign entries.

init-and-run-wiki

@@ -31,5 +31,5 @@ fi
 
 # Start the tiddlywiki server
 
-exec /usr/bin/env node $NODEJS_V8_ARGS $tiddlywiki_script mywiki --server 8080 $:/core/save/all text/plain text/html ${USERNAME:-user} ${PASSWORD:-'wiki'} 0.0.0.0 ${SERVE_URI}
+exec /usr/bin/env node $NODEJS_V8_ARGS $tiddlywiki_script mywiki --server 8080 $:/core/save/all text/plain text/html "${USERNAME:-user}" "${PASSWORD-wiki}" 0.0.0.0 ${SERVE_URI}