plugins.viasat: Add support for HDS streams.
cli: Add support for K and M suffixes to the --ringbuffer-size option.
docs: Small tweaks.
cli: Deprecate --best-stream-default and add --default-stream instead.

Resolves #381.
api: Rename Plugin.get_streams to Plugin.streams.
api: Add Livestreamer.streams method.
api: Add livestreamer.streams function.
docs: Update to reflect API additions.
cli: Fix unhandled URL resolve.
plugins.speedrunslive: Update to use session.streams().
plugins.dmcloud_embed: Update to use session.streams().