Assert: Add alias for throws called 'raises'

Brings back the original method name, for compatibility with environments that consider 'throws' a reserved word.

Fixes #663

Also moves some tests for assert to its own file, in a separate commit. The new raises test is at the end of `test/assert.js`.

The jshint exception is necessary to make it shut up about `assert[ "throws" ]` not using dot notation.
based on what I got from #663, we should entirely replace `throws` for `raises` and invert the statement above to create a backwards compatibility copy of the main `raises` into `throws`, making the former a deprecated method until 2.0.0.