• Move the license file of pyarmor from the install path of pyarmor package to user home path ~/.pyarmor
• Refine error messages so that the users could solve most of problems by the hints.
• Refine command pack, use hook hook-pytransform.py to add the runtime files.
• The command pack supports customized spec file, refer to
  https://pyarmor.readthedocs.io/en/latest/advanced.html#bundle-obfuscated-scripts-with-customized-spec-file
• In runtime module pytransform, the functions may raise Exception instead of PytransformError in some cases.
• In command register, add option --legency to store license.lic in the traditional way
• Fix platform name issue: in some linux platforms the platform name may not be right