Replace ::Config module with env vars or File::Which if required.

Previous version had config values in a generated module called
Cvs::Simple::Config.  This has been removed in this version; values of CVS_BIN
and EXTERNAL should be set via constructor args or env vars.

The legacy file will still be used if present.
Merge tag 'SC-FEATURE-remove-config-1.131120'

SC-FEATURE-remove-config-1.131120
Add a perlcritic policy.

Also move the Cvs_Test module out of the main module path.
Update repo readme
Update gitignore