SSToolkit will no longer support Cocoapods.

Fixes #187. Fixes #175. Fixes #167. Fixes #152.
Fix typo in extremityView property of SSCollectionViewExtremityTableViewCell.
Fix one more typo in SSCollectionView
Merge pull request #188 from sethfri/master

Typo Fix
Merge remote-tracking branch 'upstream/master'

* upstream/master:
  Fix one more typo in SSCollectionView
  Fix typo in extremityView property of SSCollectionViewExtremityTableViewCell.
  SSToolkit will no longer support Cocoapods.