Sort and remove unused using in /src/Apache/Cassandra
Sort and remove unused using in /src/
Sort and remove unused using in /src/
Sort and remove unused using in /src/Connections
Sort and remove unused using in /src/Linq
Sort and remove unused using in /src/ObjectSerializer
Sort and remove unused using in /src/Operations
Sort and remove unused using in /src/Thrift
Sort and remove unused using in /src/Types
Sort and remove unused using in /src/System
Sort and remove unused using in /src/Properties
Added a project for integration tests

Having both types of tests (unit and integration) in the same project it
is difficult for new commiters to understand which tests to run. It's
much easier to run unit tests than integration. Let's have to separate
projects.
Merge pull request #134 from oleksii-mdr/master

Clean up usings