Proxy configuration broken in 0.14

[jodal]

In 0.13, we supported the following setting:

SPOTIFY_PROXY_HOST = u'http://10.0.0.17:8080'

In 0.14, this was changed with the new config system. The equivalent today would be:

[proxy]
hostname = http://10.0.0.17:8080

But this doesn't work, as proxy/hostname is validated as a hostname:

ERROR    Config value proxy/hostname must be a resolveable hostname or valid IP

I suggest that we add more proxy config values, making the following a working proxy config:

[proxy]
type = http
hostname = 10.0.0.17
port = 8080

Other possible values for proxy/type include https, socks4, socks5. These values match the types accepted by libspotify. Does these types match what we can provide to GStreamer as well?

[adamcik]

See http://cgit.freedesktop.org/gstreamer/gst-plugins-good/tree/ext/soup/gstsouphttpsrc.c#n21 and http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gst-plugins-good-plugins/html/gst-plugins-good-plugins-souphttpsrc.html#GstSoupHTTPSrc--proxy for what the souphttpsrc supports. http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gst-plugins-good-plugins/html/gst-plugins-good-plugins-rtspsrc.html#GstRTSPSrc--proxy and http://cgit.freedesktop.org/gstreamer/gst-plugins-good/tree/gst/rtsp/gstrtspsrc.c#n673 for rtspsrc.

As for naming s/type/scheme/ IMO. Otherwise like I said on IRC we need to decide if we just want the individual pieces pre split and then combine them to scheme://user:pw@host:port form before setting them on the gstreamer elements that can accept a proxy property (there is a introspection API for properties, but not all elements implement it as far as I know).

[jodal]

Fixed by merge of #481.