[DONE] Online statistics plugin

[xoft]

Seems a good base. Now it needs to query the stuff periodically (in root tick?) and store it in a circular buffer, so that the last 50 or so values are stored; then use some sort of charting JS to produce the graphs. And the per-world tick duration would be especially nice to have; that will need to use the OnWorldTick() hook and store the a_Dt parameter.

How about pushing this plugin as another repo in the mc-server organization account on GitHub?