Use double quotes by convention

Signed-off-by: Abhijit Hiremagalur <abhi@pivotallabs.com>
Inject logger via constructor

Signed-off-by: Abhijit Hiremagalur <abhi@pivotallabs.com>
Spec collaboration to ensure runner is always injected correctly

Signed-off-by: Abhijit Hiremagalur <abhi@pivotallabs.com>
Encapsulate instantiation of CommandRunner

So it can be tested and branched for the upcoming dry-run mode

Signed-off-by: Abhijit Hiremagalur <abhi@pivotallabs.com>