Add phpcs to analyze, display inline results on validate.

* Adds phpcs as currently constituted as a validate task.
* Adds phpcs:validate as an operation to the validate task. Defaults to "summary" but can be overridden in config. Displays results in terminal.
* Retains phpcs:drupal for backwards compatibility.
* Adds phpcs:inspect for more detailed reporting with the "full" format.
* For reasons of code-flow & variable scope, recombines the analyze & validate files as "quality.js".

This fixes #1

I wanted to handle #18 as well, but using the ruleset as defined by the Coder module the granularity of errors is very flat, hence the addition of the "inspect" target for deeper reporting. I imagine we'll want to use inspect for a watch variant, but leaving that for #13.