Bring packaging process up to date for OpenOffice 2.3.

Bring packaging process up to date for OpenOffice 2.3.

I noticed that installing Measurements 1 into OpenOffice 2.3 gave an error and
the demo spreadsheet did not work.  Evidently something about extensions was
changed between earlier OpenOffice 2.x and OpenOffice 2.3.  I rearranged the
packaging process to follow the CalcAddins example in the SDK.  Now the types
and the implementation are in the same jar.