Generate LICENSE, related files, and headers from package.json.

At the command line:

 npm --global install licensor
cd your-package
licensor --width 72

Licensor assumes:

1. The person described by package.json's author field is the
   copyright owner and licensor.

2. The package was created in the current calendar year.

3. All *.js source files, except those in node_modules, are the
   author's work.