Generate a checksum with the fetched dependencies.
Show gopack banner only when it fetches dependencies.

Gopack gets out of your way when they are already catched.
Merge branch 'master' into checksum

* master:
  Order stats by remotes and number of occurrences.
  Add local references to the summary.
  Add import stats summary.
  Add tests for the stats analyzer.
  add --dependency-tree to show dependencies and versions
  Add subversion support.
  0.20
  Relax the version number.
  Add gopack version to the output when checking the go version.

Conflicts:
	config_test.go
	main.go
Merge branch 'master' into checksum

* master:
  fix up stats stuff that i hosed
  add travis ci badge
  i am sorry
  update build
  travis

Conflicts:
	main.go
Fail fast if one of the dependencies download fails.
merge changes in pr #27