#2 Make MashProxy Java 1.1 compatible

[Peter Warden]

The MashProxy applet currently is compiled and tested against Java 1.5. It
should be possible to run under Java 1.1 instead, and this would be
preferable as the older version is more widely deployed.

There are two places I know about where >1.1 features are used; the
thread handling uses Swing functions, and StringBuffer objects deal with
some of the page content handling. It's also possible that some of the
HTTP and URLConnection classes I use have changed.

This bug is to track the conversion of the thread and string functions, and
the investigation of what netwoek changes are needed.