Command-line utility for installing an NPM module if not present. Useful when sharing script that have global npm dependencies. Checks version numbers. Works with the following formats:
npm-assure <pkg>
npm-assure <pkg>@<version>
npm-assure <pkg>@<version range>
npm install -g npm-assure
// in build-doc.bat
npm-assure -g jsdoc ::Uses npm list; reasonably fast
jsdoc --recurse --destination doc --readme README.md app