First pass Message Part code done

[Rob Jellinghaus <ro...@unrealities.com>]

It basically does nothing, but at least it passes the functional tests :-)  Not checked in pending some feedback from YOU, as follows:

I have created
	org.apache.axis.Part
	org.apache.axis.SOAPPart extends Part
	org.apache.axis.attachments.AttachmentPart extends Part
...and a few other classes.  I have added Message.getSOAPPart and Message.getAttachments (the latter does nothing yet).

The whole thing seems to run fine.  The biggest effect was that code of the form

	... message.getAsSOAPEnvelope() ...

had to become

	... message.getSOAPPart().getSOAPEnvelope() ...

This was in quite a few places, all of which I have updated.

I have also patched build.xml to look for, and to ignore if not present, activation.jar.  If you have activation.jar on your classpath, the (do-nothing) attachment classes will be built.  If not, they will not.  The functional tests will not notice either way.

If no one violently protests, I will check this all in tomorrow.  (actually, today :-)

I will not have much more time to work on it after tomorrow, until Saturday.  (weekend hack fest!)

Cheers!
Rob