Add MPGO to supported players

[enricocid]

It seems to be working very good with mpgo (legacy mode) but don't know if it requires additional settings (or i would have send a PR)

https://github.com/enricocid/Music-Player-GO

[Pittvandewitt]

I'll happily include your music player if your player broadcasts its audio session. This is needed for Wavelet to attach audio effects per app. Legacy mode processes the global audio session and does not work on many devices. Please refer to this comment for instructions

[enricocid]

Should be fixed now :)