Merge pull request #27 from savonet/image-decoder

Add support for image decoders.
Split http and harbor input socket mutex into get and set mutexes. Use them appropriately. Also cleanup harbor's disconnect code.
Always call set_state null when set_state raised an exception.
Remove support for ufetch.

ufetch was a nice idea but it hasn't been maintained for ages and is not
part of the current git...
Moved bugtracker to github.
Rewrite gstreamer.input.* to not be blocking..
Upgrade dependency on ocaml-taglib.
Merge pull request #29 from savonet/non-blocking-gst-input

Rewrite gstreamer.input.* to not be blocking..
Update dependencies for mm an gstreamer.
We're not ready if an error happens on get_device.
Precise time unit for grace time.
Fix bug in taglib decoder where no tag would show up when year/date wasn't set.
Make gstreamer input a regular (non active) source.
Improve documentation.
Update changelog.
Prioritize changelog.
Added play/pause telnet/server commands for input.gstreamer.*
Quick first pass on the doc.
change syntax to be OCaml 3.11 compatible
Merge pull request #31 from mkonecny/master

Use OCaml 3.11 compatible syntax