added PSGet-Installer
added the nuget-install meta-runner
Added prereq etc.
changed text since it wasn't correct
added the semver meta-runner
Merge pull request #11 from jole78/meta-runner/psget

added PSGet-Installer
Merge pull request #13 from jole78/meta-runner/semver

added the semver meta-runner
Merge pull request #12 from jole78/meta-runner/nuget

added the nuget-install meta-runner