Kevin Feige did touch on The Avengers sequel and X-Men: Days of Future Past have the Quicksilver speedster in common:
“There are only a handful of characters that occupy that middle ground. Iron Man is not going to show up over there and Magneto is not going to show up over here. But there are a few gray points even after many years of negotiations…and that only happens with a character like Quicksilver, who has been a part of the X-Men, the son of Magneto in those comics, but also a primary Avenger. The characters (on the screen) are going to be very different. Other than their powers, general audiences might not even know — unless they read your article — that the two are related.
What is the "few gray points"? Wolverine?
Edit: Feige (supposedly) says there are no current plans to do 3 MCU films a year but didn't rule it out totally.