Support MPD_HOST/_PORT environment variables

[jspricke]

No description provided.

[SoongNoonien]

Hi!
Thanks for the PR. I don't think that it is desirable to modify the settings via the environment variables. I could imagine to give them priority over the settings of Plattenalbum.

[jspricke]

Thanks for the feedback, changed the patch accordingly.

[SoongNoonien]

Thanks for the update. But you broke the connect process. It is now impossible to connect via a socket if the host gsettings entry is nonempty. Also running self.config() without any safety precautions can crash the whole program.

[jspricke]

pushed a new version. The only thing I noticed when testing was that you can't connect to a different remote host when $MPD_HOST is set. To allow this we would need to make remote-connection three state or add an extra variable. I don't have enough experience with gi to know the implications, do you have some insights?