pyinstaller starts slowly

[manthey]

PyInstaller builds more easily than py2exe, but it starts very slowly as it needs to unpack everything as it goes. As a further build note, the files size produced on appveyor is nearly twice as large as py2exe on the Windows XP VM. Getting this size down may reduce the start time.

PyInstaller has many virtues over py2exe, so switching back is not an option.