Sets uploaded media filename to lowercase.
This plugin evolved from a client requirement that all uploaded media filenames contain no uppercase characters.
It was useful to me and I wanted to work through the process of releasing a WordPress plugin.
Upgradeability, portability, backwards compatibility, and other *abilities. If for some reason this function were in need of customization due to a WordPress version upgrade, the plugin will be centrally responsible for releasing the fix as opposed to updating the theme(s).