Agreement by senior EU officials in late-night talks * Exact size and breakdown of bailout remain to be decided * Private investors to participate, details being worked out * Uncertainties remain over Greek politics, IMF stance * Greek PM to present austerity plan to euro zone on Friday (Recasts with agreement in principle on new Greek bailout) By Lefteris Papadimas and Sakari Suoninen ATHENS/AACHEN, Germany June 2 (Reuters) - Senior euro zone officials have agreed in principle on a new international bailout of Greece that will give it more time to try to resolve its debt crisis, a source close to the talks said on ... (full story)