bundle2: move the fromheader closure into the class itself
The class is now directly related to this header data. We can sanely move it on
the class.
I do not like closures very much...
to build a new macosx binary package:
install macpython from http://www.python.org/download/mac
install py2app from http://pythonmac.org/packages/
make sure /usr/local/bin is in your path
run bdist_mpkg in top-level hg directory
find packaged stuff in dist directory