Run InfraKit on Windows

[friism]

• when building for Windows (which works), the executable files in build should have the .exe extension
• Named pipe should be supported in addition to unix socket:

time="2016-11-09T07:50:20-08:00" level=info msg="Listening at: C:\\Users\\Michael Friis/.infrakit/plugins/group"
time="2016-11-09T07:50:20-08:00" level=error msg="listen unix C:\\Users\\Michael Friis/.infrakit/plugins/group: socket: An address incompatible with the requested protocol was used."

[wfarner]

Some relevant discussion in #214

[chungers]

For this it probably makes more sense to go with named pipe on Windows https://github.com/natefinch/npipe

TCP support #214 is related but should be focused on 'consuming' SPI providers that exposes a JSON-RPC endpoint (say a custom instance provisioning system), rather than allowing the binaries we provide to listen on TCP ports.

[wfarner]

@chungers i was not suggesting restoring TCP support, just pointing to context. In particular, this line from the issue description:

TCP support is primarily offered as a lowest-common denominator for Windows, but we should look to named pipes for a closer analog.