doorway improvements: uninstall, uri matching, character encodings

[why the lucky stiff]

Okay, all my changes are in for 1.2.  If there are no complaints, I will 
hand-wrap it tomorrow.

The biggest change concerns uri matching.  I scrapped the 
include/exclude boxes.  It's all one box now.  And matching happens in 
the order you dictate.  I've also added uninstall and factory defaults 
buttons.

I did a bit of work on character encodings for Tidy.  It'll try to 
detect utf8 and give it faithful processing through Tidy.  Other 
encodings don't appear to need such attention.

1.3 Todo:
* The blocking on timed-out threads is seriously annoying.
* User scripting hooks for rewriting of outgoing headers.
* Javascript library to ease common tasks.
* GM_API.

_why