Added classes to store yield variables for the ssm module

Resolve "Update the README installation instructions"

Closes #10

See merge request rnsd/sammy!10

Incorporate Goran and Devin's suggestions into the
README to improve the installation instructions for
open-source sammy

Fix more ci nonsense

See merge request rnsd/sammy!11

Fix ci nonsense

See merge request rnsd/sammy!7

Use C++ ENDF reading routines to read File 3 point-wise data.

See merge request rnsd/sammy!4

Remove more container arrays

See merge request rnsd/sammy!3

Take out some arrays for cvnd3
Take out VVV
Remove use of U from covariance reading - use C++ storage

Move multiple scattering module (ssm) from f77 to f90

See merge request rnsd/sammy!2

Change ssm from f77 to f90, and implement capture
yield corrections into the new C++ code.

Add the files that .gitignore failed to port over.

See merge request rnsd/sammy!1