Create a separate CONTRIBUTING file per recent suggestions
Use the correct link to the CONTRIBUTING file
Remove overhead from the credentials test

The isRemoteURL() method is not helpful enough for test performance to waste space or thought
on making it more accurate.  It ignored git@hostname URLs which may be local or remote and the
use of that method didn't seem to dramatically improve test performance.
Merge branch 'master' into master-add-parameterized-credentials-test