Updated for symfony 2.5 + features

There's a lot going on in this PR, here are a couple of things...
- Updated for Symfony 2.5, including merging one of the existing branches for 2.2
- Updated to the non beta version of spec, fixed specs accordingly
- Nested object schema generation
- Switched to annotation_reader included with symfony
- Support for entity type's from the form guesser
- Fixed property handler sorting so that annotations can override the form guesser, etc.
- Added several other annotations, format, options, etc. to expand the functionality offered by JSON Schema
- Added ability to ignore properties from being included in the JSON Schema
- Added default titling

There are probably some other things I am missing, but in general I tried to stick with the spirit of what was originally done here.  I am currently using this in a project pretty heavily and have a vested interest in continued development of the project, specifically I'd like to add some better functional tests (phpunit) if that's palatable. I'd also like to add support for definitions, as well as metadata using the JMS Metadata package so that yaml and xml would be supported.

Feedback welcome, thanks!
99%? In the commit message for this change I linked the pertinent docs, https://github.com/stanlemon/KnpJsonSchemaBundle/commit/3b8eebd97a13ab7ee81fe0f9a3e6e3639a87eb3c#diff-7a062282b36199ff7d4904f2d9fd4f4f  I fully admit I may be misreading, but I don't think so. Let me know if you disagree.  Thanks!