Allow specifying root in `arc inlines`
Allow specifying root in `arc inlines`

Summary: Simplifies editor bindings.

Test Plan:
  $ arc inlines --root W:/devtools/phabricator/

Reviewers: epriestley

Reviewed By: epriestley

CC: vii, aran, Korvin

Differential Revision: https://secure.phabricator.com/D3229

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