Issue #791: setuptools is now required for PyInstaller installation.
Issue #826: Add new hiddenimports for SciPy hooks.
Merge remote-tracking branch 'upstream/develop' into develop

Conflicts:
	PyInstaller/hooks/hook-scipy.special._ufuncs.py
Issue #773: Remove six.py module and append pyinstaller lib dir at end of sys.path.
Issue #873: Add import hook for amazonproduct.
Merge pull request #114 from matysek/develop

Drop distribute requirement, remove six.py module, add hook for amazonproduct.