Merge branch 'il/vcs-helper'

* il/vcs-helper: Reset possible helper before reusing remote structure Remove special casing of http, https and ftp Support remote archive from all smart transports Support remote helpers implementing smart transports Support taking over transports Refactor git transport options parsing Pass unknown protocols to external protocol handlers Support mandatory capabilities Add remote helper debug mode Conflicts: Documentation/git-remote-helpers.txt transport-helper.c