vmnetx-generate has problems with large package members on Python < 2.7.4

[bgilbert]

When generating a package with one or more members larger than 4 GB, struct complains:

'L' format requires 0 <= number <= 4294967295

This is a Python zipfile bug, fixed in Python 2.7.4. On Python 2.7 this produces a struct.error exception and is fatal. On Python 2.6 it is only a warning, but the resulting Zip file has an incorrect local file header (the size is modulo 4 GB). This doesn't affect VMNetX because zipfile reads the file size from the central directory, which is written correctly. However, other utilities (e.g. unzip) may declare the package file invalid.