Fixes torrent file uploads, which were broken in 2.1.0.

In 2.1.0 every .torrent upload failed with "Received invalid torrent file",
on every client. Magnet links were not affected. Uploads work again.

Torrent names are also read more accurately. Names containing emoji or other
uncommon characters now arrive intact, and where a torrent carries a separate
UTF-8 name, that name is used.

New: Flood is now supported as a client.

Fixes:
- Torrent names with 4-byte UTF-8 characters (such as emoji) are decoded correctly.
- Profiles are migrated correctly from older versions.
- Clicking a magnet link is only intercepted when a profile is set to handle it.
- The options form stays in sync with the selected profile.
- qBittorrent requests no longer fail the login check when the URL has a port.
- Rebuilding the context menu no longer produces duplicate entries.

### Bug Fixes

• client: transform URLs to URL patterns for request introspection (cf1aca3), closes #46
• remove trailing slash from URLs before concatinating (07f963a)

### Bug Fixes

• options: correctly link autostart label to checkbox (dfa7014)

This is an entire rewrite of the add-on. This will allow to more easily incorporate new features in the near future. Apart from some cosmetic updates, this release is fully backward-compatible.

Important
Depending on your previous version, you might need to re-create your profiles.

- Multiple client profile support
- Magnet links support

Support for magnet links and qBittorrent added (thanks felfert).

Fix duplicate definition of torrentToWeb namespace

Add Deluge client support.

Added Transmission client adapter.

Add minimum firefox version 48.