Refactoring for InheritsByReference:
* RowPermissions now use Expressions instead of function delegates; added Func to ServerDom which returns RowPermissions Expression
* RowPermission tests updated to reflect changes
* FilterExpression changed to return expression instead of IQueryable and added function to optimize and execute expression on a given query
* RowPermissions will now optimize its expression before executing it on a query
* FilterExpression tests updated to reflect changes
* Added ReplaceWithReference class for replacing parameters in expression trees