OverDrive Download .odm Button per bemehiser

Automatically modifies the "Listen now in browser" button to "Download .odm file" to allow easy downloading of the .odm file for use in legacy mp3 file apps.

Previously OverDrive (used by many public libraries) presented a "Download Mp3" button to download an .odm file which allowed for download of mp3 files. In the last couple years this button has been hidden, and OverDrive has been pushing users to use a low quality web player instead of downloading mp3. This extension modifies the web player button to instead download the .odm file so users can download and listen to mp3 files in a player of their choice.