[Mingw-cross-env-list] package removal

[Marcel Wysocki]

its me again, sorry for spamming the list today :D

i guess it would be useful to be able to remove
installed packages together with their dependencies.
all it would need would be the following:

during installation:
1) write down every file the package installs into
    intalled/packagename
    easiest way to achieve this would be a find
    before and after installation

during removal:
1) remove files listed in installed/packagename
    as long as they are not listed in any other file in
    installed/*
2) remove installed/packagename
3) check if package has dependencies
4) if it has jump to 1) and do the same
    if not we are done

that way it would be easier to test changed to packages