* Added function for updating a media item's filepaths on-disk
* Added placeholder action to source page
* Turned the file sync into a job and properly hooked it up to the controller
* Added ability to specify overwrite behaviour when downloading media
* Added helper for redownloading media items
* renamed media redownload worker to disambiguate it from similarly named methods
* Added new redownload option to source actions dropdown
* Refactored MediaQuery to use a __using__ macro
* docs
