returning float type for floats; fix logging; fixing and rationalizing tests.

[celeduc]

Functional changes

• Fixed a bug in which float values were not returned as type float (along with a new test for this).
• Fixed a bug in logging which caused failure after closing a log, making log closure meaningless unless the connection was shut down. This was order-dependent and would cause any test that runs after test_usage.rb to fail.

  Tests

• All of the tests now run and are compatible with each other.
• There are still two broken tests in test_lobs, but that appears to be a real bug (which causes an orphaned CLOB).
• Broken tests are listed in failing_tests.txt.

[treeder]

Wow, nice pull request! ;) I'll review this today.

[treeder]

Thanks!