Module Image Assets

Allows for calling images stored in a module's assets folder with the assets library. To use pass the module name to the image url.

for example: site_url('images/default.png?module=blog');
will provide an image stored in [...]/bonefire/modules/blog/assets/images/default.png
Module Image Assets Fix

fix $img_file override I missed.
Fix code statement.
Documentation for Module Image Assets
Merge pull request #931 from thedudeguy/master

Can now use module-based images with the images controller.
Merge pull request #2 from ci-bonfire/master

Master