File Entity Input Filter

Adds an input filter that can be used on any text format that replaces links to file entities with links to the actual file itself.

This could be useful in a number of circumstances. My original use case was that I was using LinkIt to output links to files, but I wanted to link to the internal file directly, not the URI of the file entity in Drupal.

Nothing special is needed--simply output site-relative links to any file entity, and this input format will replace the link destination.