Merge branch 'next' into 'master'

Merge branch 'next' into 'master'

* 'next':
  Change server_mode=='dumb' to just a dumb_server_mode bool.
  Teach bup about URLs and non-ssh remotes
  Don't generate midx files in dumb server mode
  Add optional dumb-server mode
  git.CatPipe: set a buffer size on the subprocess to increase performance.
  Improve test pass condition
  Adds examples for strip, strip-prefix and graft to bup save's documentation
  Adds --graft option to bup save.

Conflicts:
	lib/bup/t/thelpers.py