Reorganized tests directory structure

* Moved NUnit tests to tests/ directory, next to src
* Moved all other old tests to tests/old
* Moved solution files outside of src to project root
  (in view of nuget usage)
Upgraded to NUnit 2.6.2 via nuget
Overhaul of unit tests for isolation/efficiency

- The test database schema is now created when the first fixture runs,
  no more scripts
- Each test is now responsible for loading whatever data it needs into
  the database.
- All the different tables have been merged into one, called data.
- The data table is truncated before each test runs.
- We no longer create two connections for each test (v2, v3), only one
- General all-around refactoring
Missing renames in test project files
Merge pull request #44 from roji/test_cleanup

Unit test overhaul