Prefer CommonJS over window env

Hi,
I've patched my.class.js to support running in CommonJS environment when running inside a browser.
With existing code, we never register in module.exports, since "window" is present.

Note, if existing code is using a global "module" for something else, then we will overwrite any exports property there, and we wont register on window..
Maybe window.my should always be configured if window is present?