Adding rush_op_set_drupal_variables()
Fixing $alias setting in rush_op_set_drupal_variables()
Small fixes in rush_op_set_drupal_variables() based on feedback in https://github.com/palantirnet/rush/pull/21/files
Merge pull request #21 from stevector/feature-20-drupal_variables

Add new Rush Operation: set_drupal_variables