Zotero File Storage megacommit

- Group file sync via Zotero File Storage
- Split file syncing into separate modules for ZFS and WebDAV
- Dragging items between libraries copies child notes, snapshots/files, and links based on checkboxes for each (enabled by default) in the Zotero preferences
- Sync errors now trigger an exclamation/error icon separate from the sync icon, with a popup window displaying the error and an option to report it
- Various errors that could cause perpetual sync icon spinning now stop the sync properly
- Zotero.Utilities.md5(str) is now md5(strOrFile, base64)
- doPost(), doHead(), and retrieveSource() now takes a headers parameter instead of requestContentType
- doHead() can now accept an nsIURI (with login credentials), is a background request, and isn't cached
- When library access or file writing access is denied during sync, display a warning and then reset local group to server version
- Perform additional steps (e.g., removing local groups) when switching sync users to prevent errors
- Compare hash as well as mod time when checking for modified local files
- Don't trigger notifications when removing groups from the client
- Clear relation links to items in removed groups
- Zotero.Item.attachmentHash property to get file MD5
- importFromFile() now takes libraryID as a third parameter
- Zotero.Attachments.getNumFiles() returns the number of files in the attachment directory
- Zotero.Attachments.copyAttachmentToLibrary() copies an attachment item, including files, to another library
- Removed Zotero.File.getFileHash() in favor of updated Zotero.Utilities.md5()
- Zotero.File.copyDirectory(dir, newDir) copies all files from dir into newDir
- Preferences shuffling: OpenURL to Advanced, import/export character set options to Export, "Include URLs of paper articles in references" to Styles
- Other stuff I don't remember

Suffice it to say, this could use testing.

components/zotero-service.js

@@ -64,6 +64,9 @@ var xpcomFiles = [
 	'style',
 	'sync',
 	'storage',
+	'storage/session',
+	'storage/zfs',
+	'storage/webdav',
 	'timeline',
 	'translate',
 	'uri',