Add seek support

[mazkolain-zz]

Add track seeking support to the streaming proxy.

CherryPy has a useful function called serve_fileobj(), that takes care of all partial content request stuff. The stream could implement a virtual file obj that takes care of translating requested ranges to seek calls to libspotify.

[ghost]

In my own language, does this mean the problem with seeking forward / backward is being fixed in future release?

Now... when i use the forward key in XBMC twice, it will skip the current (playing) track and start playing the next track.
Maybe this isn't a big Issue for the main public, but i'm listening a lot of vinyl version tracks which have a long intro and outro and I appreciate it when this "seeking problem" can be fixed.
Thanks in advance!

[mazkolain-zz]

That's right.

When XBMC attempts a seek, the proxy server rejects this operation (as it's unimplemented), which in turn causes XBMC to skip to the next track.

[ghost]

Great! +1

For me this is the most important thing cause I do seek a LOT ;-)
Looking forward to it.