Change repo url to roots org

Ref: roots/grunt-wp-version#1
Rename task from wprev to version
Contributing
Refactor task

Change task name from wprev to version

Roots work perfectly when querystring enable but useless when querystring disable.

wp_enqueue_style( $handle, $src, $deps, $ver, $media );
wp_register_script( $handle, $src, $deps, $ver, $in_footer );

Roots default set for wp_enqueue_style ($media) and wp_register_script ($in_footer)

Fixed roots/grunt-wp-version#1
Roots with filename revving instead of querystring

When querystring not present, version task will use filename revving for default and ensure wp_enqueue_style and wp_register_script has correct setting.

Ref:
  * http://codex.wordpress.org/Function_Reference/wp_enqueue_style
  * http://codex.wordpress.org/Function_Reference/wp_register_script
Update tests

Adding hash function so filename more dynamic. No need to update test filename everytime we update to the latest main.min.css and scripts.min.js

Update css and js test to latest Roots (04efa7b)
Bump 0.1.5
Merge pull request #3 from hariadi/develop

Refactor task
Merge pull request #4 from roots/develop

Refactor task