Link Brew, add troubleshooting steps, add example
Link Brew, add troubleshooting steps, add example

I had some trouble following the installation instructions; I've added some troubleshooting steps, linked to Brew (for Windows folks like me), and provided an example of what was meant by running `colony` from the command line.
tessel/t1-runtime,tessel/t1-runtime,tessel/t1-runtime,tessel/t1-runtime,tessel/t1-runtime