3.4/develop

Fully embraced the composer way of doing things, added requirement of PHP 5.4+, and added some fancy new 5.4 stuff.
hmm, see also @acoulton comments below, it's very thoughtful.

As far as I understand, he suggests that we can live without array initializations and construction chaining, so that people who want to still back-port this into 5.3, would be easier for them.

We can always use the new features of PHP 5.4 (for ex: `Closure::bind`), but no need to force ourselves to use all the new features - that sometimes only add some sugar.