Delete unused var declaration.
Fixed caching.
Removed another unused var.
Auto-detection of server-mode, better caching.

The SERVER variable is no longer needed. RSS .xml file is now cached for a very short time, so as to make loading faster, and hopefully reduce bann a little. Use a more common User-Agent to try to cut down bann. Added ability to test whether a key is in the Cache.
Library import list made cleaner.
Save Cache when it's new.

So as to avoid crashes on first fetch.