Rolled back Selenium version due to "Invalid Protocol Error: None" when creating sessions on real devices.
Fixed issue with device serial being ignored for real devices.
Test added to prove issue.
Additional tests added to fully cover changed method before refactor.
Undo Selenium version rollback
Changed back to "HttpMethod" from "HttpVerb"
Merge pull request #517 from richard-stowe/master

Issue with getting physical devices by serial/udid