Update the szczur environment file to match current environment variable syntax

[mgduda]

This merge updates the szczur.yaml environment file to match the current environment
variable syntax.

As of the merge commit 6f55178, the syntax for specifying environment variables
changed.

[mgduda]

This PR fixes Issue #15 .

[MiCurry]

@MGuda, the library section looks good in szczur.yaml, but the MPI section is incorrect. You can specify the MPI section in a similar way to the compiler section:

  GNU-9.2.0:
    name: gnu-9.2.0
    compiler:
      name: gnu
      version: 9.2.0
      path: /Users/duda/local/gcc-9.2.0
      executables:
        - gcc
        - gfortran
        - g++
    MPI: 
      version: x.xx.x
      PATH: /Users/duda/local/gcc-9.2.0
      executables:
        - mpicc
        - mpifort
        - mpic++

[MiCurry]

I will also note that I've got a hopefully final change to the main specification of the environment file coming soon, which you can find in my branch here: https://github.com/MiCurry/SMARTS2/tree/env_spec. As well as updating the specification to be more consistent, it also contains a few more checks to the environment file and updates all of the error messages to match the specification.

If you would like, I can update szczur.env to match the new environment in that branch after merging this PR.

[mgduda]

I've just force-pushed an updated branch that I think should resolve the MPI environment issue.

[MiCurry]

@mgduda, this PR looks good. However, after the last PR #17 the file is again out of date. However, PR #17 contains update to the environment file parser that will walk you through the changes you'll need to make. So if you rebase this branch on master, and try to run list tests you'll get error messages on what needs to be change.

The changes are mostly for the capitalization of keywords (i.e. compiler becomes Compiler, name becomes Name, etc.)

Let me know if you have any questions or problems.