Adds better npm support 

Hi! Awesome library and I can already see many funny use cases for this. 

As far as I could tell, it looks like you are planning to push this to package managers later on? And it looks like you are planning to support CommonJS as UMD is used? I think it will make sense to change the `package.json` main property to your dist file making it easier to use the module with CJS as well. The current main path is pointing to a temporary file that is cleaned up. I can't see any downside to having the main property pointing to the dist file. I can't see any use cases where you would want the main property pointing to an AMD file. 

In addition this adds a `.npmignore` file, omitting the images and demo from the module as they are unnecessary assets to have in a distributed package.

Please let me know what you think.