Add support for a make dev

[timothysc]

Make dev should update the generated .yaml to use

imagePullPolicy: IfNotPresent

• we could add other bits there.

[timothysc]

This will involve ksonnet generating updated.yaml target.

Should discuss tomorrow.

[timothysc]

@liztio

When developing and testing we want to have a dev target which basically does some minor variable substitutions on a different generated output .yaml that we can add to the .gitignore file.

So the workflow would be ~= :

make dev
-->generated a quickstart-dev.yaml (changed defaults) 
submit and test quickstart-dev.yaml 

Some of the substitutions would be:

1. increase verbosity of the logging
2. switch imagePullPolicy: IfNotPresent
   ...? Perhaps @hausdorff or @chuckha have other things they would like to see in a dev target?