Added docs for metrics-guice.
Added docs for metrics-guice.

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