EAGLESIX-2892 broke out and expanded DepsTracker into own class
EAGLESIX-2892 ported ParsedDeps
EAGLESIX-2892 added DepsTracker unit tests
EAGLESIX-2689 updated Nary to 2.6.5
EAGLESIX-2687 fixed some leftover naming issues
EAGLESIX-2687 Renamed files per convention(for templates)
EAGLESIX-2690 expressions FixedArity
EAGLESIX-2892 cleaned up DepsTracker tests, todos
EAGLESIX-2705 expression AnyElementTrue 2.6.5 port
EAGLESIX-2892 added ParsedDeps unit tests
EAGLESIX-2892 removed dependencies code from DocumentSource
EAGLESIX-2892 moved old unit tests, fixed formatting
Merge branch 'feature/mongo_2.6.5_expressions' into feature/mongo_2.6.5_dependencies
EAGLESIX-2693 updated addDependencies to use new deps
Merge branch 'feature/mongo_2.6.5_expressions' into feature/mongo_2.6.5_expressions_FieldPath
EAGLESIX-2693 updated, added missing unit test
EAGLESIX-2693 fixed whitespace and formatting
Merge branch 'feature/mongo_2.6.5_expressions' into feature/mongo_2.6.5_expressions_Nary
EAGLESIX-2651: Nary: mv for NaryExpressionT split into NaryExpression and NaryExpressionBaseT (to match the original source code)
EAGLESIX-2651: Nary: reorganize code, minor bugs, test utils

* split NaryExpressionT into NaryExpression and NaryExpressionBaseT to more closely match the original source code
* split expr test utils into their own file