Update regex parser to be more lenient

The parser will now match *keyword* to loggers with a namespace such as
`keyword:foo`, `keyword:bar`. This is exactly the same behaviour as the `debug` module.

Updated `exports` to `module.exports` as it is the recommended usage form. 
Also, omitting brackets on a single-line statement is a valid stylistic choice. I think it's best to respect the coding style of the module you're contributing to (even if it's not your own style).