[DAS2] das1->das2 proxy adapter

[Andrew Dalke]

As part of my effort to make sure DAS2 supports at least what
DAS1 can do, and to simplify migration from DAS1 to DAS2,
I have over this week developed a partial proxy adapter.  It's
a DAS2 server which translates the request then forwards it
to a DAS1 server (including the "segment" and "overlaps"
feature filters).

It takes the results and reformats them into DAS2 format.  I
had used a template approach for this but that proved slow for
for large responses.  I rewrote the code so I generate the XML
by hand, which also gives me a chance to put in a lot more
validation code for DAS1.  The goal there is to ensure that
I catch all the extensions people added to DAS1.


					Andrew
					dalke at dalkescientific.com