* Italian shares, Monte Paschi rebound after early losses* Euro down but rebounds from 20-month low near $1.05By Jamie McGeeverLONDON, Dec 5 (Reuters) - Italian shares rose on Monday as investors bet against an immediate snap election in Italy following Prime Minister Matteo Renzi&aposs resignation after defeat in a constitutional reform referendum.Markets had been jolted by the scale of Renzi&apo