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

This merge includes a significant number of 3.3 bugfixes and changes because the branch has not been merged up for some time - please review carefully.

Somewhat amazingly, the only merge conflicts in 78bccef were:

* the changes to UTF8::clean that had been fixed separately (but the same) in both 3.3 and 3.4
* the changes to Kohana_CoreTest to resolve hardcoded directory paths (same fix in both 3.3 and 3.4)
* two separate sets of additions to Kohana_TextTest.

And the build is green, so either I've not broken any of your new 3.4 series changes, or you've not been writing tests for them.... :grinning: