Feature/mongo 2.6.5 matcher comparison match

Test cases are failing. There is either an issue in one of the test cases that was ported (that is, it's failing for Mongo as well), there's an issue in the matching code in one of ComparisonMatch's base classes, or the related control flows have been ported have been implemented incorrectly.

The changes to the code are largely to make conventions consistent within the file and make the code itself more consistent with the C++, however some redundant code was removed.