[Fortress-interest] Portability and classpath fixes

[David Chase]

Revision 97 contains an accumulation of fixes to
Cygwin detection, classpath setting, and build.xml.

The Fortress interpreter requires Java 1.5 (or better).

Getting Fortress still requires subversion (we're
all using 1.4+, though I think 1.3.1 should work).

Information on installing subversion can be found here:

http://subversion.tigris.org/project_packages.html#binary-packages

Building Fortress requires ant (1.6.5 or better), which can
be downloaded from:

http://ant.apache.org/bindownload.cgi

if you do not have it already.

David