Introducing lighthouse-keeper: more reliable and faster lighthouse management

@rossbearman has done a phenomenal job creating lighthouse-keeper, which allows for the discovery and power state management (on/off) of both 2.0 and 1.0 lighthouses. This is a big improvement over the existing binaries that MixedVR-manager was using. Most notably to users: starting and stopping your VR sessions will take about half as long as they did before. Moreover, you'll experience a lot fewer instances when one lighthouse remains on and the other is off, requiring you to turn on/off SteamVR a couple times to get them both into the correct state.

The time for MixedVR Manager to complete all startup events (given two 2.0 basestations) is about 38 seconds (down from 60 seconds), and the time to complete all shutdown events is about 26 seconds (down from 34 seconds).

This release includes lighthouse-keeper v0.1.0