[NGRINDER-560] make report visible without login

Modified the security configuration file.
[NGRINDER-559] improve monitor chart plot

After the first time request of monitor data, the monitor plot is
already saved in a map. Just need to replot it is ok.
[NGRINDER-559] using [] to get value from map

if the key contains ".", there will be problem to get value from map
with this key.
Merge branch 'master' of https://github.com/nhnopensource/ngrinder