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 additional 3.3 bugfixes and changes - please review carefully. 

In particular, there was a merge conflict on Minion_CLI because f9f4d47dd441c877f removed the Minion_CLI::password method from 3.4/develop. This commit was authored by @WinterSilence and appears to have been merged by @kemo  in #92 - but I have not been able to find much detail in either the PR or commit message to identify why this was, or indeed whether it was intentional as the vast majority of the rest of that commit is just comment formatting and documentation.

I have kept the 3.4/develop version of that class - so if we did ever want to reintroduce Minion_CLI::password we'd need to apply the bugfixes from 3.3 that have been left out of this merge.