+ browser caching and mousehole

[why the lucky stiff]

Well, I might as well be straightforward on this.

Just checked in: MouseHole does allow browser-caching of pages.  
However, it assists the browser in distinguishing between a plain page 
and a proxied page.

The most common use cache is user scripts.  If you request 
proxylike.user.js, you'll get an Etag and a modification time and the 
browser will hold on to that unless MouseHole intervenes in the request 
headers.

MouseHole basically adds a "MH-" prefix to the Etags.  So if 
proxylike.user.js normally has an Etag of "7a7b949d311cc51:119e", 
MouseHole's version of it is called "MH-7a7b949d311cc51:119e".  This 
means that as you switch between the proxy and the browser, you should 
be able to separately pull cached pages for each.  This only happens for 
pages which list 'text/html' in the 'Accept' header.

MouseHole will dump its Etag list when you restart it.  I will probably 
allow this to be toggled off/on per-script.  Some scripts will rewrite 
pages several times.

_why