Compatibility with libre.fm

[FoxxMD]

Libre.fm implements the last.fm api spec. It would great if this library could be used for libre.fm as well, but there is a blocking issue:

Just like lastfm-node-client (which this looks like its based on), this library has options for http functions hardcoded, including the hostname. Please make the request options, or Agent used, configurable by the end-user.

[scriptex]

Hello, @FoxxMD and thank you for this request!

I am currently under heavy load and not sure if I can work on that in the short term. However, I am accepting pull requests so if you feel like doing it - please open one and add your changes, I will be more than happy to review and add them to the library.

Thank you!