Update OSVR API to provide SteamVR with all the info it wants

[godbyk]

trafficstars

This issue is to track the properties and information that SteamVR may request of the OSVR plugin. Specifically of note is the information that we need to write new OSVR-Core or RenderManager APIs to provide and code that should be migrated from the plugin to other OSVR libraries.

The following list is not exhaustive. As more items are discovered, please add comments below and I'll update this list.

• [x] Detect if direct mode is enabled or disabled. This is done for Windows (see PR #53), but the code should live elsewhere.
• [x] Get the EDID VID and PID values. (See PR #53.)
• [x] Get the display name for the HMD.
• [x] Get the refresh rate of the HMD's display.
• [ ] Get the firmware version of the display.

[Balderick]

The ability to create a system report to confirm the suggestion above and give other relevant information to provide an easy means for consumers to access and share useful information when trouble shooting or requesting support.