Update submodule vim/bundle/airline 35d2240...5c18be4

* vim/bundle/airline 35d2240...5c18be4 (3):
  > Merge branch 'solarized-inactive-like-vertsplit'
  > Revert changes to s:NM, add s:NMi for inactive windows
  > Merge branch 'solarized-inactive-like-vertsplit'