Oil dips towards $109 after steep gains, eyeing Ukraine

* Ukraine peace deal falters, with no rebel surrender * Technical problems delay reopening of Libyan port * Iran, world powers to start drafting accord next month (Previous SINGAPORE, updates prices, adds quote) By Alex Lawler LONDON, April 21 (Reuters) - Oil eased towards $109 a barrel on Monday, giving up some of the previous session's rally as traders saw little new to augment their worries ...