Upgrade to Nest 1.0.1

Created for issue #2 

I've made the following enhancements:
1. Upgrade to Nest 1.0.1
2. upgrade to json.net 6.0.4
3. add ability to specify the default index within the connection string (legacy way of specifying within the elmah config still supported).
4. new unit tests for new functionality
5. let ES define the ID, it will be a bit less consistent but it will be considerably faster