Minor: couple more usability tweaks to the runnodes script

gradle-plugins/cordformation/src/main/resources/net/corda/plugins/runnodes

@@ -4,6 +4,10 @@
 set -euo pipefail
 export CAPSULE_CACHE_DIR=cache
 
+# Allow the script to be run from outside the nodes directory.
+basedir=$( dirname "$0" )
+cd "$basedir"
+
 if which osascript >/dev/null; then
     # MacOS X: open each node in a in new tab.
     first=true
@@ -15,13 +19,12 @@ if which osascript >/dev/null; then
             script="$script
     tell application \"System Events\" to tell process \"Terminal\" to keystroke \"t\" using command down
     delay 0.5
-    do script \"cd $rootdir/$dir; java -jar JAR_NAME; exit\" in window 1"
+    do script \"cd $rootdir/$dir; java -jar JAR_NAME && exit\" in window 1"
             first=false
         fi
     done
     script="$script
 end tell"
-    echo "$script"
     osascript -e "$script"
 else
     # Some other UNIX, probably Linux