Bring Perl_Companies.yaml up to date

[vmbrasseur]

The yaml file (and the entire process related to it) has fallen into disarray.

1. Review all closed pull requests & make sure the data is represented in the yaml file
2. It looks like all companies whose names start with a lowercase letter, oddly, not in the yaml file (but ARE in .md and .csv). Add them back in.
3. Fix inconsistent quoting in yaml file (some name entries are quoted, some not)
4. Confirm ALL entries in .md/.csv are in the yaml file (see lowercase names task above)
5. Review the yaml processing script ( Use a yaml master file #28 )
6. Update 'how to contribute' doc accordingly