Setup test to verify non-SRD information is not included.

I believe Travis-CI will run for free against a github repo. As long as PRs are used rather than direct merge to master, a simple test script could be written to read the JSON files, and validate the items.
For example, load the `monsters-SRD.json`, loop all the `names` and verify a hard-coded list of `names`. If anyone adds additional, tests fail.

Look at the existing JSON files like monsters-SRD.json to understand the structure. The test needs to read this file, extract the 'names' array, and compare it against a hard-coded list of allowed names. Check the repository for existing test setup (likely in a test/ directory) and see if there's a CI configuration (like .travis.yml). Writing a simple script in TypeScript/JavaScript that runs on CI and fails if extra names are added is the goal.

Written by the indexing model from the issue text.