make node-speaker node10x compatible, use internal stream node module

[hlolli]

This is actually no deadly necessary pull request. This mainly fixes bunch of deprecation warnings from Nan. I was in an attempt to fix a problem with new thread-workers in Node10 so I made these changes. But then found out that it wasn't the root of my problem nodejs/node#21481 otherwise the tests run, produces expected audio on my computer, all deps are bumped, with the readable dep removed in favor of the internal stream module provided by nodejs ecosystem. The old readable-stream module is mostly a polyfill for browser compatability as far as I understood it, bumping it to v3x caused errors with node-speaker.

Sorry about the noise, had to move this PR to another branch.

[hlolli]

I bet my changes to mocha weren't fetched in CI tests? Some module cacheing I would guess.

[LinusU]

Thanks for the PR, in the end we went with another approach here: #137. Sorry for not getting to this earlier ☺️