WASHINGTON — A new study details how President Barack Obama has been inviting his Obama Foundation donors to events at the White House, a venue that obviously won’t be available to him to entertain mega contributors in a few months. The Obama Foundation, created on Jan. 31, 2014, has to date only 39 contributors, with the money coming either from individuals or foundations controlled by Obama supporters. The nonprofit, nonpartisan Maplight Foundation found that 15 of the 39 have been to the White House for small meetings