A brain-dead replacement for svn:externals (and soon Git submodules)

Mainly, xtrn doesn't depend on the revision control system. This means that you can pull in code from heterogeneous systems with a single command.

Just create an Externals file in the root of your project, require the xtrn gem and run xtrn (again, in the root of your project).

The format of the Externals file is as follows, note that the username and password will not be cached:

---
- url: svn://svnhost/dir/to/external/codebase
  path: checkout/to/here
  type: svn
  username: optional_username
  password: optional_password
- url: svn://svnhost2/another/thing
  path: this/one/goes/here
  type: svn