Full implementation of Kraken's public market data API. Also, improved
deserialation with respect to using the raw service.
Merge pull request #283 from jamespedwards42/develop-kraken

Full implementation of Kraken's public market data API & Custom Deserialization
manually added Vircurex module from pull request #285, fix forward merging issues, cleaned up a bit.
Merge branch 'develop' of https://github.com/timmolter/XChange into develop