Improve the online documents. [Elastic3rd manual](https://elastic3rd.readthedocs.io/en/latest/index.html) Add `elastic3rd run` and `elastic3rd post` command. Please use `-h` for detail help.
2.4.2
- Support all classes of crystal, from cubic to triclinic - Support CASTEP (windows or linux, under Materials Studio) and VASP - Support Python2 and Python3 - Support pip installation
1.1.1
1.1
Calculate the 3rd order elastic constant of crystal(now only support for cubic).