Pyarmor

* Fix webui bug: raise "name 'output' is not defined" as running `packer`

* Add new restrict mode 2, 3 and 4 to improve security of the obfuscated scripts, refer to :ref:`Restrict Mode`
* In command `obfuscate`, option `--restrict` supports new value 2, 3 and 4
* In command `config`, option `--disable-restrict-mode` is deprecrated
* In command `config`, add new option `--restrict`
* In command `obfuscate` the last argument could be a directory

* Fix issue: the output path isn't correct when building a package with multiple entries
* Fix issue: the obfuscated scripts raise SystemError "unknown opcode" if advanced mode is enabled in some MacOS machines

* Fix issue: it will raise error "Invalid input packet" to import 2 independent obfuscated packages in 64-bit Windows.

* Fix bug of command `pack`: the obfuscated modules aren't packed into the bundle if there is an attribute `_code_cache` in the `a.pure`

* Fix bug: it could not obfuscate more than 32 functions in advanced mode even pyarmor isn't trial version.