License proliferation

[ghost]

I think we should limit the licenses to only the most well-known/the most useful.

I created a new branch without the lesser-known or less useful licenses. (I went by Google Code's license recommendations from 2006-2010: I removed the non-software CC licenses, the BSD/MIT-redundant permissive licenses, and a few others.)

This will make it easier for us to maintain the project, and will also make it less complicated for the end user.

You mentioned keeping licenses used by larger projects. Large projects usually have their own protocols for accepting contributions. Removing their licenses from this project should not cause too many issues for those projects' contributors.

At least we should remove the least-used or project-specific licenses. @rgbkrk mentioned before that he'd rather not include very little-used licenses.