Improve documention/Readme

[jtebert]

Updates to Readme:

• List known issues (such as GCC 8.1 bug)
• Provide virtual machine instructions (possibly)
• Explicitly state that it only supports Linux
• List contributors and their contributions (perhaps split out into CONTRIBUTORS.md)
• Add section about contributing
• Add section about support (look at issues, open issue, who to contact)
• Include licence info (once determined)
• Explain how to use/include the static library for other experiments (modularity)
• Include info on multi-threading (when, how much, etc)
• Make and include a logo

Documentation improvements (what's generated by Doxygen)

• Exclude things (mostly classes) that are technically public but aren't actually meant to be used directly
• Clarify battery life/setting battery
• More examples
• Clearer documentation of timing (for debug)

[r-barnes]

I'm working on a cmake build which should help with the modularity (richard/make branch).

[jtebert]

I saw that -- that's awesome! I looked into cmake at one point but got intimidated by it.

[r-barnes]

I very nearly have Mac compilation (easy with cmake), but I believe the mystery GCC 8.1 bug is at work here too.