Phing 2.8

Added all code quality, documentation, and task running dependencies as required-dev packages in composer.json, then refactored Phing build.xml to work with the latest versions of each of those packages.

Now supports:
 * phing
 * phpunit
 * phpmd
 * php_codesniffer
 * php copy paste detection
 * php dependency analysis
 * phpDocumentor2
 * php LOC static analysis