Pyarmor

* Fix pack issue: it will raise `UnicodeDecodeError` when the source path includes non-ascii characters(217)
* Fix obfuscate issue for Python2: it will raise `UnicodeDecodeError` when the source path includes non-ascii characters
* Refine pack command: it will print the output of PyInstaller to the console either

* Refine pack command. Now it's easy to pack the obfuscated scripts with an exists `.spec` file, just specify it by `-s`, refer to https://pyarmor.readthedocs.io/en/latest/advanced.html#bundle-obfuscated-scripts-with-customized-spec-file

* Change the plugin search policy, do not support enviorment variable `PYARMOR_PLUGIN`, but search folder `plugins` in the pyarmor package path.
* Add a new path `plugins` in the package source, there are several common
plugins. So it's easy to check internet time by this way
shell
pyarmor obfuscate --plugin check_ntp_time foo.py

Before that both of these lines should be inserted into `foo.py`
python
{PyArmor Plugins}
PyArmor Plugin: check_ntp_time()

* Fix pack bug: `pyi-makespec: error: unrecognized arguments: -y` if extra options are passed
* Document command `pack` in details: https://pyarmor.readthedocs.io/en/latest/man.html#pack

* Fix pack issue: `pyi-makespec` doesn't work
* Add new platform: `uclibc-armv7`
* Fix issue: guess encoding failed if there are non-ascii characters in the second line
* Document how to work with Nuitka,
https://pyarmor.readthedocs.io/en/latest/advanced.html#work-with-nuitka

* Add new option `--enable-period-mode` in the command `licenses`
* When running the obfuscated scripts it will check license periodly (per hour) if the option `--enable-period-mode` is set in the license file

* Fix bug: the command `pyarmor runtime --platform alpine.x86_64` raises error (201)
* Fix bug: the platform `linux.armv6` doesn't work in Raspberry PI ZW, rebuild the dynamic library with `-march=armv6 -mfloat-abi=hard -marm`