Updating CONTRIBUTING.md with wiki content (#3525)
Updating CONTRIBUTING.md with wiki content (#3525)

* Updating contributing instructions in repo (replacing wiki)
alfonsokim/nupic,rhyolight/nupic,scottpurdy/nupic,ywcui1990/nupic,subutai/nupic,scottpurdy/nupic,vitaly-krugl/nupic,alfonsokim/nupic,neuroidss/nupic,scottpurdy/nupic,alfonsokim/nupic,numenta/nupic,ywcui1990/nupic,lscheinkman/nupic,rhyolight/nupic,rcrowder/nupic,subutai/nupic,rcrowder/nupic,subutai/nupic,lscheinkman/nupic,lscheinkman/nupic,numenta/nupic,neuroidss/nupic,rcrowder/nupic,marionleborgne/nupic,ywcui1990/nupic,pulinagrawal/nupic,vitaly-krugl/nupic,rhyolight/nupic,neuroidss/nupic,marionleborgne/nupic,numenta/nupic,vitaly-krugl/nupic,marionleborgne/nupic,pulinagrawal/nupic,pulinagrawal/nupic