Merge pull request #17 from apojha/master

[#11 ]See commit messages for details - issue 11
[#9] Removing thread wrapper around starting scassandra as it is now async
[closes #18] Defaulting query consistency to ONE
Merge branch 'master' of github.com:chbatey/scassandra-java-client
[#11] Retrieiving previous prepared statement primes.
[#9] Improving logging when primes fail.
[#9] Adding toString to When object
[#11] adding deletion for prep statements and some refactorings of the priming client