Added Pods documentation to gitignore
Refactor refreshing unread notes

Since a Note can't be marked as unread, we only check unread status for
the unread notes that we know.
Adding skeleton framework to permit native account creation and blog signup.
Styled up the create account view.
Styled up the create blog view.
Continued to tweak Create Blog and Create Account Views.

* Added language option to create account view.
* Added blog visibility to create blog view.
* Modified WordPressComApi class to properly utilize newly modified API endpoints
* Modified create account page to use the two new endpoints instead of one.
* Created WPAsyncBlockOperation to allow us to chain a series of dependent
  NSOperation classes to one another and have successive operations fail should
  an operation have any of it's dependent operation's fail.
Fixing issue where WPCom logo didn't center in landscape on Create Account and Create Blog Views.
Removing WebSignupViewController artifacts.
Fixed a few errors with the language list.
Added error message when user hits the rate limit for WordPress.com account creation.
Modifying blog creation to set isAdmin to true always.
Various fixes and refactorings