Merge abstract standard

Intended to require PHP 5.5.0 or newer as sniffs should rely on a php 5.5. tokenizer for new keywords and syntax.

Obviously a vagrant box would be needed to develop for those, which we not yet have available (it is easy to set up, but if we can avoid submodules and chef solo that would be wasted effort).

Requiring PHP 5.4.0 as minimum version and will mark PHP 5.5-only tests as skipped for now.