No longer need the 2to3 import fixer.

$ 2to3 --no-diffs -n -w -f import Bio BioSQL Tests Doc Scripts
RefactoringTool: No files need to be modified.

$ 2to3 --no-diffs -n -w -f import -d Bio BioSQL Tests Doc Scripts
RefactoringTool: Refactored Bio/Phylo/Applications/_Fasttree.py
RefactoringTool: Refactored BioSQL/BioSeqDatabase.py
RefactoringTool: Files that were modified:
RefactoringTool: Bio/Phylo/Applications/_Fasttree.py
RefactoringTool: BioSQL/BioSeqDatabase.py

These two changes are trivial and not actually helpful for
use of the doctests as examples.