Update Contributing.md to clarify the nodeunit to karma transition
Update Contributing.md to clarify the nodeunit to karma transition

snuggs/jsdom,Sebmaster/jsdom,fiftin/jsdom,mzgol/jsdom,fiftin/jsdom,Joris-van-der-Wel/jsdom,nicolashenry/jsdom,mzgol/jsdom,tmpvar/jsdom,snuggs/jsdom,nicolashenry/jsdom,mzgol/jsdom,tmpvar/jsdom,Joris-van-der-Wel/jsdom,Sebmaster/jsdom,nicolashenry/jsdom,Sebmaster/jsdom,Joris-van-der-Wel/jsdom,Zirro/jsdom,fiftin/jsdom,Zirro/jsdom