Merge tag '0.4.9' into develop

Tagged 0.4.9
Mininal typo in README

I just add the `new` to `Response` :)
Merge pull request #7 from joksnet/patch-1

Mininal typo in README - thanks to @joksnet
Fix Invoker to map subclasses

When invoking a method which has a parameter of class X, Invoker will
properly map class parameters which are instances of a subclass of X.
Updated HTTP Foundation to 2.5.x
TravisCI: Added testing on PHP 5.6
Updated CHANGELOG for 0.4.10 release
Merge branch 'release/0.4.10'