Update install docs to point to OpenBSD packages.
Merge pull request #448 from ibara/develop

Update install docs to point to OpenBSD packages.
plugins.beattv: Make use of the validation API.
stream.rtmpdump: Fix proxy support.
plugins.ard_mediathek: Refactor to use the validation API.
plugins.filmon_us: Refactor to use the validation API.
Add plugin for connectcast.tv.

Resolves #423.
plugins.ustreamtv: Refactor to use the validation API.
docs: Update theme and use sticky navigation.
cli: Remove leftover unicode_literals import.
travis: Fix only one zip getting uploaded.
docs: Add a player page.
docs: Add missing file.
plugins.viasat: Add support for viagame.com.
docs: Rename argarse_ext to ext_argparse.
docs: Replace sphinxcontrib.issuetracker with my own extension.
docs.ext_github: Fix Python 2 compatibility.