Accept-Encoding: gzip for RSS downloader

[magao]

It appears that the RSS downloader does not send an Accept-Encoding: gzip header, meaning that the RSS feeds are downloaded uncompressed. RSS feeds are highly compressible.

Advantages:

1. Reduction in required bandwidth - may make the difference between successfully downloading a feed or updating a tracker in a heavily loaded situation.

2. Reduces I/O load on RSS feed server.

Disadvantages:

1. Requires gunzip capability in uTorrent;

2. May slightly increase CPU load on RSS feed server (in practice this tends to be more than compensated for by the reduction in I/O).

[magao]

I guess there would probably be the same benefits for tracker updates (if they're not using it already).