Use cellClass for WPTableVC instead of newCell

- WPTableVC registers the cell with a default cell identifier for its subclasses

- Clean up WPTableVC and remove all swiping functionality as it wasn’t used
Use cell registration for more table views
Use cell registration and clean up creating account
Use cell registration in note details

- Remove other swipe view code from WPTableVC
Register cells in EditSiteVC + cleanup

- Remove dead code - save button is hidden unless fields are filled, so validation code not used

- Add red colour used to WPStyleGuide instead of macro
Merge branch 'develop' of github.com:wordpress-mobile/WordPress-iOS into issue/699

Conflicts:
	WordPress/Classes/AddUsersBlogsViewController.m
	WordPress/Classes/BlogListViewController.m
	WordPress/Classes/CreateWPComAccountViewController.m
	WordPress/Classes/EditSiteViewController.m
	WordPress/Classes/ReaderPostsViewController.m
	WordPress/Classes/WPTableViewController.m
Merge pull request #711 from wordpress-mobile/issue/699

#699 Use cell registration instead of inline cell creation where possible. WRT to @astralbodies comment, not fixing the string as the file is deleted in https://github.com/wordpress-mobile/WordPress-iOS/pull/692