Pip-licenses

* Ignore spaces around `--fail-on` and `--allow-only` parameters

* Fix the order in which multiple licenses are output

* Handle multiple licenses better with options `--fail-on` and `--allow-only`
* Small change in output method for multiple licenses, change the separator from comma to semicolon
* Up to 3.4.0: `Python Software Foundation License, MIT License`
* 3.5.0 or later: `Python Software Foundation License; MIT License`

* Implement new option `--packages`

* Fix license summary refer to `--from` option

* Improves the readability of the help command