Initial interface for AccountService
Refactor Blog+Jetpack to use AccountService instead of WPAccount
Refactor syncBlogs to accept a WPAccount as a parameter
Refactor BlogListVC to use AccountService instead of WPAccount
Refactor BlogSelectorVC to use AccountService instead of WPAccount
Refactor CreateAccountAndBlog to use AccountService instead of WPAccount
Refactor EditMediaVC to use AccountService instead of WPAccount
Refactor EditSiteVC to use AccountService instead of WPAccount
Refactor JetpackSettingsVC to use AccountService instead of WPAccount
Refactor EditMediaVC to use AccountService instead of WPAccount
Refactor remaining classes to use AccountService instead of WPAccount
Removed all stateful code from WPAccount and put into AccountService

Still need to extract remote code from AccountService.
Initial remote AccountService implementation

Still need to rip out all of the networking code from the view controllers on account creation, etc.
Removed saving the default account - it's not thread safe
Merge branch 'develop' into feature/refactor-wpaccount-into-service

Conflicts:
	WordPress/Classes/NotificationsFollowDetailViewController.m
	WordPress/WordPress.xcodeproj/project.pbxproj
Merge branch 'develop' into feature/refactor-wpaccount-into-service

Conflicts:
	WordPress/Classes/NotificationsViewController.m
Merge pull request #1528 from wordpress-mobile/feature/refactor-wpaccount-into-service

Refactor WPAccount into Service layer object(s)