AutoDockTools (Prepare subset) for Py3k

Subset of AutoDockTools v1.5.7, tailored just to run:

• prepare_receptor4.py
• prepare_ligand4.py

This was ported by running 2to3 and then manually fixing incompatibilities, such as:

• Python 2.7's string module wrapper (admire the hackiness in _py2k_string.py)
• Inconsistent indentation (spaces vs tabs) - might have introduced one bug or two...
• Raised "string exceptions"
• map(None, [...]) -> zip_longest([...])

Disclaimer

This has not been tested thoroughly at all. Results are not guaranteed to be the same as in the original distribution.