Add standalone build for 3.4 series

Merges the 3.3/develop branch up to 3.4/develop and updates the travis and composer configs for 3.4.x - continues kohana/kohana#50
@enov yeah, that felt most sensible - since I imagine that 3.3 and 3.4 will be live for the foreseeable future, and therefore (once we get a 3.3 bugfix release out) the github homepages for the packages will always give a good overview regardless of which branch is the default.