Waypoint on the continuous improvement path

Many improvements in this release since v0.2, which you may have already been using given our continuous-deployment design. No backward-compatibility-breaking changes.

Extensive update: fully-configurable path tree, use of device descriptors for auto-routing, and more.

• Updated server and client internal data structures, for:
  • more efficient data transfer
  • fully-configurable path tree, with support for single or multi-level aliases for semantic name use with no additional performance hit.
• Unification of several internal libraries into one, reducing DLL count.
• Partial to complete auto-configuration of aliases based on JSON device descriptor data embedded in plugins.
• Full access to external (local or remote) VRPN servers/devices with Tracker, Button, and Analog interfaces. (Previously, only experimental support for Tracker devices) See the updated osvr_server_config.externalvrpn.sample.json
• Support for auto-detecting a USB serial port name by VID/PID.
• Configurable contents of /display now controlled and configurable by the server: see osvr_server_config.dSight.json for config info.

Breaking changes:

• To support the data structure updates, some internal messages were changed, so v0.2+ client libraries can only communicate with v0.2+ servers: v0.1 and v0.2 do not interoperate. (However, client ABI or overall client API did not change, so you should be able to just replace the DLLs without recompiling your client application.)
• If your device driver was not submitting a JSON device descriptor, it will be mostly inaccessible as that is used to populate the path tree. See the example on how these work.
• The method of configuring access to external VRPN servers has changed, so if you're using that functionality, see the updated sample config files.
• Plugins have been renamed, and many configuration files were able to be simplified greatly. See the updated sample config files.