[edit] readme
[add] statistics presence
[add] statistic sparkline
[add] sparkline screenshot
[add] stats persistence
[add] statistics on mongodb
[add] statistics flush and purge
[add] index opt for stats
Merge branch '5e98f3d2da46b84b5b68c6e71b48aad615fc8da3' into toremote
Merge branch 'toremote'
[add] MongoQ update method, test