arc browse: Support line number and reduce conduit call
arc browse: Support line number and reduce conduit call

Summary:
support common "filename:line number" format.
Also, remove redundent conduit call.

Test Plan: arc browse with and without :33 suffix.

Reviewers: epriestley, vrana

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D6451

alexmv/arcanist,jra3/arcanist,dguo-coursera/arcanist,aik099/arcanist,calblueprint/arcanist,PageUpPeopleOrg/arcanist-patches,folsom-labs/arcanist,dguo-coursera/arcanist,julkiewicz/arcanist,sneakpeeq/arcanist,haskell-infra/arcanist,Symplicity/arcanist,phacility/arcanist,hach-que/arcanist,calblueprint/arcanist,memsql/arcanist,hach-que/arcanist,r4nt/arcanist,memsql/arcanist,wxstars/arcanist,codelabs-ch/arcanist,coursera/arcanist,jra3/arcanist,alexmv/arcanist,calblueprint/arcanist,codelabs-ch/arcanist,folsom-labs/arcanist,r4nt/arcanist,kevinseelbach/arcanist,eSpark/arcanist,fivestars/arcanist,phacility/arcanist,sneakpeeq/arcanist,folsom-labs/arcanist,coursera/arcanist,folsom-labs/arcanist,PageUpPeopleOrg/arcanist-patches,memsql/arcanist,uber/arcanist,wharris/arcanist,Khan/arcanist,julkiewicz/arcanist,KieranHayes/arcanist,wxstars/arcanist,coursera/arcanist,PageUpPeopleOrg/arcanist-patches,kevinseelbach/arcanist,julkiewicz/arcanist,wxstars/arcanist,aik099/arcanist,kevinseelbach/arcanist,wikimedia/phabricator-arcanist,zhihu/arcanist,sneakpeeq/arcanist,codelabs-ch/arcanist,Khan/arcanist,uber/arcanist,wharris/arcanist,fivestars/arcanist,zhihu/arcanist,Symplicity/arcanist,wikimedia/phabricator-arcanist,hach-que/arcanist,wxstars/arcanist,Khan/arcanist,phacility/arcanist,uber/arcanist,calblueprint/arcanist,haskell-infra/arcanist,Symplicity/arcanist,alexmv/arcanist,KieranHayes/arcanist,codelabs-ch/arcanist,codelabs-ch/arcanist,fivestars/arcanist,KieranHayes/arcanist,eSpark/arcanist,wikimedia/phabricator-arcanist,chundongwang/arcanist,fivestars/arcanist,chundongwang/arcanist,kevinseelbach/arcanist,r4nt/arcanist,wharris/arcanist,aik099/arcanist,phacility/arcanist,eSpark/arcanist,Khan/arcanist,zhihu/arcanist,eSpark/arcanist,chundongwang/arcanist,chundongwang/arcanist,haskell-infra/arcanist,wharris/arcanist,alexmv/arcanist,sneakpeeq/arcanist,PageUpPeopleOrg/arcanist-patches,uber/arcanist,julkiewicz/arcanist,aik099/arcanist,phacility/arcanist,dguo-coursera/arcanist,wikimedia/phabricator-arcanist,KieranHayes/arcanist,coursera/arcanist,hach-que/arcanist,zhihu/arcanist,r4nt/arcanist,memsql/arcanist,jra3/arcanist,jra3/arcanist,dguo-coursera/arcanist,haskell-infra/arcanist,Symplicity/arcanist