small test speed up

don’t actually do an npm install when it’s output isn’t tested. Instead only test that the npm install task is called.
misc cleanup
Merge pull request #2684 from stefanpenner/reduce-npm-calls-during-tests

test cleanup
use ui.writeError in lib/cli/cli.js

fixes GH-2254
Refactor command model and added command unit tests
Merge pull request #2342 from fivetanley/use-ui-write-in-cli

use ui.writeError in lib/cli/cli.js
Updates broccoli-asset-rev to 1.1.1
Merge pull request #2687 from rickharrison/asset-rev-111

Updates broccoli-asset-rev to 1.1.1
Refactored command model parseArgs
Merge pull request #2686 from trabus/command-unit-tests

[WIP] Refactor command model
Update README.md
Disable default lookup & active generation logging
Merge pull request #2694 from tomdale/disable-verbose-logging

Disable default lookup & active generation logging
#2548 Suggestion message when using '.' at creation
Close #2691 ember server --proxy crashes and exits when Internet connection is lost
update package.json
Merge pull request #2707 from vais/issue2691

Close #2691 ember server --proxy crashes and exits when Internet connect...
Merge pull request #2704 from esbanarango/master

#2548 Suggestion message when using '.' at creation
Properly handle `ember.js` -> `ember.debug.js`.
Merge pull request #2712 from rwjblue/ember-debug-file

Properly handle `ember.js` -> `ember.debug.js`.