baby steps - it puts the provider into the configuration
add the notion of a source and all the plumbing that comes with it; add error returns to some methods that were calling exit(1) from outside main.go making it hard to test
Don't fail if SCM dir already exists
Merge branch 'master' into mihasya-providers

* master:
  Simplify installation by not trying to generate another array.
  Add `gp installdeps` to the README.
  Add `installdeps` command.
Complete provisioners.

- Fetch code when the dependency already exists.
- Add subversion support.
Cleanup Dep#Scm.
Add some notes in the README about Sources and Providers.
Fix typo in the project name.
Rename Provider to Scm.

- Move Dep.Scm() to NewScm(*Dep)
Merge pull request #51 from calavera/mihasya-providers

Sources and Providers v2