EAGLESIX-2707 added test cases to better match the c++ tests.
Merge branch 'feature/mongo_2.6.5_expressions' into feature/mongo_2.6.5_expressions_Add
Merge branch 'feature/mongo_2.6.5_expressions_And' into feature/mongo_2.6.5_expressions_Add
EAGLESIX-2707 Added the 'commutitive...' function to AddExpression. Added 'optimize' test cases. comment out test cases relating to dates which we do not support.
EAGLESIX-2701 merged in Add and Add
EAGLESIX-2701 Minor fixes to OrExpression. Made test cases work.
Merge branch 'feature/mongo_2.6.5_expressions' into feature/mongo_2.6.5_expressions_Or
Merge branch 'feature/mongo_2.6.5_expressions_Add' into feature/mongo_2.6.5_expressions_Add_And_Or
Merge branch 'feature/mongo_2.6.5_expressions_Or' into feature/mongo_2.6.5_expressions_Add_And_Or
EAGLESIX-2700 Merged 3 different expressions as changes had been made in the wrong branches.  Addressed errors in the Add expression related to nulls. Corrected test cases.
Merge branch 'feature/mongo_2.6.5_expressions' into feature/mongo_2.6.5_expressions_Add_And_Or
Merge branch 'feature/mongo_2.6.5_expressions' into feature/mongo_2.6.5_expressions_Add_And_Or
EAGLESIX-2651: Add: better sync w/ 2.6.5 code and tests
EAGLESIX-2651: expr: minor OO fixes and docs
EAGLESIX-2651: Add: hack for require order issue

* require order of Expression and AddExpression is somehow breaking:  new ConstantExpression(123) instanceof Expression
EAGLESIX-2651: Add: fix jshint error
EAGLESIX-2651: And: better sync w/ 2.6.5 tests
EAGLESIX-2651: And: rm old unused test code
EAGLESIX-2651: And: rm old unused test code
EAGLESIX-2651: And: better sync w/ 2.6.5 code