[WIP] Feature/diagnostics

A flexible, event-based runtime diagnostics component.

Full documentation available in `docs` folder:
https://github.com/Thinkscape/ZFTool/blob/feature/diagnostics/docs/DIAGNOSTICS.md

**Notice** 
This PR is not ready for merge. I have aliased `dev-master` in `composer.json` for stdlib and console components to work around critical bugs. This PR will be ready for merger after the release of ZF2 version `2.1.5`.