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. 
`module.exports` is only required when you want to set a singular export. It's fine to attach properties to `exports`, and I'd prefer if you removed this change - IMHO it just reduces to the signal-to-noise ratio (and clutters your PR :)