[iOS] Allow NSURLconnection to use delegate queue

Client now has a public property to let the connections use a delegate
queue instead of the calling thread
[iOS] Code review updates and minor cleanup

Update test case test
Update how push.h is included
Add newline to MSLoginController due to issue with Doxygen
Merge pull request #313 from phvannor/login-main-thread

[iOS] Allow NSURLconnection to use delegate queue