Added some instrumentation to retieve stats from the threadpool
Added some instrumentation to retieve stats from the threadpool

Two new methods to ThreadPool:

1 - #__begin_stats__
This turns on stat-keeping. You can only call it once.

2 - #__stats__
Retrieves all the current statistics. Locks the stats array while it
makes a duplicate. Best to call after #join.

envato/rake,bentley/rake,hsbt/rake,ruby/rake,taiganakagawa/rake,Vanzct/rake,tmornini/rake,esasse/rake,askl56/rake,envato/rake,ipmobiletech/rake,zzak/rake,hsbt/rake,jaustinhughey/rake,pjump/rake,utilum/rake,88rabbit/rake,ruby/rake,codedogfish/rake