Breaking up the importer's huge icommon.py file

[vila]

>>>>> Max Bowsher <_ at maxb.eu> writes:

<snip/>

    > "package_importer" is a bit long. "udd" works for me, especially as the
    > project lives in lp:udd.

+1

    > Once we have a namespace, I'm inclined to move the tests there too -
    > that would sidestep naughty packages which install top-level "tests"
    > modules on the system path.

+1

        Vincent