added timeout for poltergeist, changed ways poltergeist uses "click" in "sign_in_spec.rb", otherwise tests may fail
reversed changes made to remove dependency on some "omniauth" strategy implementations. it turns out it's much more cumbersome to remove those as those would be needed in running test code in clients depending on this gem, such as "spree_weixin_merchant"
Merge branch '2-3-stable' of https://github.com/dapic/spree_social into 2-3-stable
reversed changed pulled in from GitHub server (next time we should do this in a cleaner way)