Adding (missing) drupal_uri value to drush_cmd resource in site-install provider.
Initial commit of drush_php_eval provider.
Fixes to providers to not use @new_resource. (Still learning Ruby.)
Removing references to build_path.
Used the wrong classname in load_current_resource.
Adding variable provider for variable-set and variable-delete. Changes to helper to assist with idempotence.
Adding ability of drush_cmd to accept Array for arguments and options.

Adding shell_input attribute to drush_cmd. This will allow for piping.

Adding (very) basic exception handling to drush_cmd's shellout.

Standardizing the naming and arrangement of attributes in providers.
Fixes to drush_vget (formerly drush_vget_json) in helper library.