Update README.md, mostly to use ${CLUSTER}. (#431)
Update README.md, mostly to use ${CLUSTER}. (#431)

* Update README.md, mostly to use ${CLUSTER}.

Replaced YOURCLUSTER, foo, and <your_config> in example command lines with ${CLUSTER}.
Left YOURCLUSTER for examples inside the config file.
Updated helm output and usage, especially for search and install of kubernetes-dashboard.
Added instructions to bring the cluster up prior to the examples for accessing the cluster.

* Updated README.md

Joe pointed out that more clarity was needed in a couple of places.

* Update README.md

yenicapotediaz/k2,samsung-cnct/kraken-lib,alejandroEsc/k2,leahnp/k2,leahnp/k2,yenicapotediaz/k2,samsung-cnct/kraken-lib,samsung-cnct/k2,alejandroEsc/k2,samsung-cnct/k2,samsung-cnct/kraken-lib