Update VisualVM screenshot.
Update VisualVM screenshot.

Closes #351.

chenxianghua2014/metrics,kevintvh/metrics,slovdahl/metrics,dropwizard/metrics,tempredirect/metrics,mt0803/metrics,thelastpickle/metrics,timezra/metrics,mtakaki/metrics,mnuessler/metrics,signalfx/metrics,infusionsoft/yammer-metrics,mattnelson/metrics,rexren/metrics,randomstatistic/metrics,gburton1/metrics,ChetnaChaudhari/metrics,mveitas/metrics,gburton1/metrics,slachiewicz/metrics,dropwizard/metrics,fcrepo4-archive/metrics,ind9/metrics,wfxiang08/metrics,mspiegel/metrics,ohr/metrics,jasw/metrics,jplock/metrics,mveitas/metrics,egymgmbh/metrics,unitsofmeasurement/metrics,cirrus-dev/metrics,bentatham/metrics,Banno/metrics,fcrepo4-archive/metrics,valery1707/dropwizard-metrics,dropwizard/metrics,AltitudeDigital/metrics,infusionsoft/yammer-metrics