fix startweb.sh syntax

webapp/startweb.sh

@@ -1,6 +1,8 @@
 #!/bin/sh
-if [ -f "`command -v screen`"]; then
+if [ -f "`command -v screen`" ]; then
     screen -S EnlivenMinetest node server.js
 else
-    nohup node server.js &
+    nohup node server.js & | exit 1
+    echo "node server.js is running in background. terminate as follows:"
+    echo "  killall node"
 fi