Pyarmor

* Raise exception other than `sys.exit(1)` when pyarmor_runtime fails
* Refine cross protection code to improve the security
* Fix issue: advanced mode fails in some MacOSX machines with python2.7

* Add platform data file `index.json` to source package
* Refine core library for platform MacOSX

* Fix issue: advanced mode doesn't work in some MacOSX machines.
* Fix issue: can't get the serial number of SSD harddisk in MacOSX platform

* Fix issue: the `_pytransform.dll` for windows.x86_64 is not latest

* Fix issue: the option `--exclude` in command `obfuscate` could not exclude `.py` files
* Refine command `pack`

* Fix issue: check license failed if there is no environment variable `HOME` in linux platform
* Add new value `3` for option `--package-runtime`, the bootstrap code will always use relative import with an extra leading dot
* The command `runtime` also generates bootstrap script `pytransform_bootstrap.py`
* Add option `--inside` in command `runtime` to generate bootstrap package `pytransform_bootstrap`
* Document how to run unittest of obfuscated scripts, refer to
https://pyarmor.readthedocs.io/en/latest/advanced.html#run-unittest-of-obfuscated-scripts