New feature: PHPCSDev ruleset

[jrfnl]

New feature: PHPCSDev ruleset

This adds a new external PHPCS standard called PHPCSDev for use by sniff developers to check the code style of their sniff repo code.

Often, sniff repos will use the code style of the standard they are adding. However, not all sniff repos are actually about code style.

So for those repos which need a basic standard which will still keep their code-base consistent, this standard should be useful.

The standard checks the following:

• Compliance with PSR-2.
• Use of camelCase variable and function names.
• Use of normalized arrays.
• All files, classes, functions and properties are documented with a docblock and contain the minimally needed information.
• A small number of arbitrary additional code style checks.
• PHP cross-version compatibility, while allowing for the tokens back-filled by PHPCS itself.
  Note: for optimal results, the project custom ruleset should set the testVersion config variable.
  This is not done by default as config variables are currently difficult to overrule.
  Refs:
  • Change ruleset processing to be top-to-bottom instead of processing tags in groups squizlabs/PHP_CodeSniffer#2197
  • Overruling arbitrary config directives squizlabs/PHP_CodeSniffer#1821

The ruleset can be used like any other ruleset and specific sniffs and settings can be added to or overruled from a custom project based ruleset.

Includes adding QA checks for this ruleset to the Travis script.

QA: add code style check for the code in this repo

This:

• Adds a custom PHPCS ruleset which uses the PHPCSDev ruleset to check the code style of code in this repo.
• Adds convenience scripts to the composer.json file to check the code of the repo.
• And allows for individual developers to overload the phpcs.xml.dist file by ignoring the typical overload files.