Support hls source
plugins.justintv_common: Fix VOD subscription warning.
Merge branch 'source' of https://github.com/bashtech/livestreamer into develop
docs: Now also available in FreeBSD ports!
stream.hds: Support Akamai HD player verification, via “pvhash” parameter.

Reads <pv-2.0> element from manifest and sets up query string parameters to
be added to each fragment URL.
stream.hds: Calculate and cache player hashes via “pvswf” parameter.

Hashes are saved in a new “stream.json” cache file. The SWF file is requested
with an “If-Modified-Since” condition if a cached hash is already available.
Merge pull request #222 from vadmium/pv

Add support for Akamai HD player verification to the HDS module
stream.hds: Some minor style tweaks.
stream.hds: Simplify last modified check.