adding ignore patterns

Hello @sboora, @chaosgame, @sugunasubra, 

Please review the following commits I made in branch 'giannic-output'.

da63caf79cefc393c51ba0d8b4b2da167b5b51e4 (2014-06-11 14:47:31 -0700)
adding ignore patterns

R=@sboora
R=@chaosgame
R=@sugunasubra
Oh wait, are you gonna push that upstream? In this case, disregard my comment about style.