refactor: build and serve commands

[jkuri]

Close #265.
I refactored build and serve commands so we will have more control on it.
The ng new command now generates angular-cli-build.js file instead of ember-cli-build.js.

The successful build message now looks like:
Built Angular2 project successfully in 2268ms. Stored in "dist/".

Later we can add sizes of assets, size of generated dist dir, ... (production build) in that message.

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