Improvements around starting figwheel from the REPL

• I added back figwheel-sidecar/get-project-builds which was removed in 0.5.4
  its now here to stay.

Improved the expressiveness of (start-figwheel!)

before (start-figwheel!) only optionally took a configuration. Now it
takes optional build-ids as well.

So you can do this:

(start-fighweel! "dev" "admin")

And it will pull in the config from the environment and start
autobuilding the supplied build ids.

Or you can supply a config and build ids ...

(start-fighweel!
  {:figwheel-options {:server-port 4000}
   :all-builds [{:id ...}]}
   "dev" "admin")

I have also beefed up the error checking and feedback around this call.