Pyconcrete

* Fix bug: 73 58
* Update installation environment variable to `PYCONCRETE_PASSPHRASE`
* Remove default passphrase

* Fix pip installation issue

* Support Python3.9 & Python3.10

* Support Python3.8
* Fix pyconcrete.exe PY_Finalize exception issue 71
* Fix threading global variable issue 61 60
* Fix python 3.7 link issue on Mac

* Support Python3.7
* pyconcrete-admin support ignore file pattern 24
* pyconcrete-admin support multiple source files 43
* Fix double release memory issue 37

Support windows build with `AppVeyor`, fix severy windows build issues