Merge branch 'il/vcs-helper'

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