Don't dismiss error if tapped near the help button

To avoid accidentally dismissing the view when the user was trying to tap one of the buttons, add some padding around the button frames when calculating if a button has been tapped.

See http://cl.ly/image/0r053r082g1N
Fixed issue where logging in with a wordpress.com site that wasn't primary resulted in another site being selected.
Allow 'tap to dismiss' from any page on the second nux walkthrough.
Fixed issue where WordPressXMLRPCApi was incorrectly flagging a DudaMobile site.
Replaced PLCrashReporter with Crashlytics

props @sendhil
Removed some logging messages

Those were useful while developing, but right now they're just noise
Avoid initialising a navigation controller with a nil root
Merge branch 'crashlytics' into release/3.6.1
Use known URL when editing existing sites

Disallow editing URL/username for existing sites and use what's known
Fixes a problem when editing password on custom domains on
wordpress.com, since the SSL certificate won't be valid for the custom
domain
Changing some Mixpanel events into properties in order to optimize usage.
Adding limit reached error message to blog creation api call.
Don't show an error if user canceled upload
Modifying WordPress.com account creation to limit the username to 50 characters.
Improved URL encoding

Taken from AFNetworking for better compatibility
Track crashes
Don't show an empty toolbar on Notifications
Fixed rotation problem on post media view
Don't reset the editor frame when it appears

fixes #1587
Fix some build warnings on PostMedia xib
Improved cookie verification

Fixes #1593 and who knows what else.

Previously, we checked for the existence of a wordpress_logged_in cookie
to decide wether we needed to authenticate or not. We didn't check if it
was for the right user, so best case scenario the user would end up with
a login page.

Reader checks were similar, so even after sign out and sign in with a
different account you got the previous user posts in the reader, at
least until it refreshed.

On top of that, the generic web view was checking for cookies on
kMobileReaderURL instead of the URL we were trying to load.