Fix: Allow enki[.py] to import from the local copy of enki if it exists, or
       from the Python library if not.
     Fixes #162.
Fix: Restore shebang for Unix.
Docs: Update Windows/Unix notes.
Clean: Remove unused import.
Fix: Handle special case for PyInstaller (sys.path empty).
Fix: Update PyInstaller build for windows to work with bin\enki.py startup script.
Do not use relative import, which is allowed only for a package