[meta] Implement automated code style checks for core

We have formal coding standards for Drupal and I think following those coding standards should be a hard requirement for any patch to get in to core.

qa.drupal.org already has support for running Coder reviews over all submitted patches. What it doesn't do is return a failed test in the event that code style is bad.

So what I'm proposing here is a few things:

1. Contrib patch: Ensure that all coding standards are being detected by Coder. #1266450: Identify and implement coding standards not covered by Coder Review
2. Code change: Clean up all code style errors in code per the Code Review tab on http://qa.drupal.org/head-style. #1266446: Core-wide code style cleanup
3. Policy change: Require that all new patches comply 100% with the coding standards (perhaps as a Gate. If a patch is following code standards, but coder reports that code standards are not met, a patch should be submitted to Coder. #1266454: Policy change: Require perfect code style for all new patches
4. CI change: Make qa.drupal.org return failing tests for bad code style. #1266444: DrupalCI should return failed for poor code style - php

Suggested Approach

So that we don't have a huge slew of patches, webchick suggested that we write a script to take care of the code style changes. Grammar Parser and Coder may help with this.

In addition, the coder code style review doesn't detect certain issues and returns false positives on some issues.

Not detected example: Comments should be written with a leading active verb and a period at the end, like this: "Returns such and such object containing foo." Coder (when I checked yesterday) did not detect that error (which is present in authorize.php).

False positive example: update.php does not have translatable strings (there's no instance of t() or get_t() anywhere in the file). Coder still reports that strings should be wrapped in t().