Ruby driver tests passing after initial refactor

* Set up tables for each test
* Clean up random tables after tests
* Move duplicate code into helper module
* Make tests independent of order (hopefully)
* Replace global variables with method calls
Reformatting code, swap assert_equal order

assert_equal order should be expected, actual. Doing this the right way
gives better error messages.
Move nested methods to helper module

nesting methods in Ruby does not affect scope
Tests only need one table
Merge pull request #205 from presidentbeef/reorganize_ruby_driver_tests

Reorganize Ruby driver tests