Separate version from command version

[Lewiscowles1986]

Pre-commit to #166

Expected Behaviour

Version command works as-is.

Current Behaviour

Not modified

Possible Solution

Pending PR

Steps to Reproduce (for bugs)

faas-cli version

Context

Merging #166 keeps stalling, lets get this done separately. We can then push the user-agent (which uses version) or push without user-agent using version and either close this or integrate later.

Your Environment

• Docker version docker version (e.g. Docker 17.0.05 ): 17.09.0-ce

• Are you using Docker Swarm or Kubernetes (FaaS-netes)? swarm

• Operating System and version (e.g. Linux, Windows, MacOS): linux (should work for all, known brew edits needed)

• Link to your project or a code example to reproduce issue: N/A