Scratchpad:Media in services proposal

These are yet quite random thoughts on media in service problems. Related to bug 885150.

I think media needs more options to save dialog: if total service file size is below 50MB, these options are by default collapsed, otherwise shown options could be as follows: When using the second option a directory named "filename-media" is made which accompanies the service file.
 * Include media files
 * Copy media files to corresponding directory
 * Do not include media files

Finding media files when loading the service is always the same, no differentiation, to the first match:
 * if file details (size and MD5 [SHA1?] for <=50MB files or name and size for >50MB files) for <50MB files) have a match in local files database, local file is used
 * if there is a media directory with the exact right name present, it is looked for that media file
 * if media file is included in service file, the file is unpacked to openlp media directory and used
 * if none of the above matches, user is being asked to relocate the file (it might have new name, but not type, e.g you cannot replace image file with a presentation)