Don't print clear-line escape sequence in json output

Summary: Refactored server connection so that I don't have to put the escape sequence printing
inside ClientUtils.connect where it doesn't know about all of args.

Reviewed By: @joelbeales

Differential Revision: D1413257
Add a json output mode for Autocomplete

Summary: -Move autocomplete's result type inside of AutocompleteService.
-Move result to json logic inside AutocompleteService so that both the IDE and hh_client can use the same code
-Send objects from hh_server to hh_client instead of formatted text
-Format text in hh_client based on whether or not output_json is set.

Reviewed By: @jwatzman

Differential Revision: D1412317