Added set PickerWheel endpoint.
Added set PickerWheel endpoint.

Summary:
marekcirkos Please review.
Closes https://github.com/facebook/WebDriverAgent/pull/150

Differential Revision: D3260643

Pulled By: marekcirkos

fb-gh-sync-id: 4009fa44ca9ff4f02fbaac5a0f642d0ef84a9ea2
fbshipit-source-id: 4009fa44ca9ff4f02fbaac5a0f642d0ef84a9ea2

qa-dev/WebDriverAgent,qa-dev/WebDriverAgent,rafael-chavez/WebDriverAgent,riccoyu/WebDriverAgent,calabash/WebDriverAgent,PiranhaTeam/WebDriverAgent,b1ueshad0w/WebDriverAgent,PiranhaTeam/WebDriverAgent,zenzhu/WebDriverAgent,ymin/WebDriverAgent,b1ueshad0w/WebDriverAgent,PiranhaTeam/WebDriverAgent,Gogle/WebDriverAgent,rafael-chavez/WebDriverAgent,ymin/WebDriverAgent,calabash/WebDriverAgent,qa-dev/WebDriverAgent,qa-dev/WebDriverAgent,drptbl/WebDriverAgent,rafael-chavez/WebDriverAgent,b1ueshad0w/WebDriverAgent,riccoyu/WebDriverAgent,Gogle/WebDriverAgent,zenzhu/WebDriverAgent,riccoyu/WebDriverAgent,zenzhu/WebDriverAgent,ymin/WebDriverAgent,drptbl/WebDriverAgent,Gogle/WebDriverAgent,b1ueshad0w/WebDriverAgent,ymin/WebDriverAgent,riccoyu/WebDriverAgent,calabash/WebDriverAgent,PiranhaTeam/WebDriverAgent,PiranhaTeam/WebDriverAgent,drptbl/WebDriverAgent,Gogle/WebDriverAgent