Fix#606 (marked stale in 2018, but now reopened). User reports that, under some circumstances, `oldCalculatedValue` will be used as the result when an unsupported function is part of a formula (this seems like a sensible treatment), but, in other cases, the unsupported function is ignored, or has an unpredictable effect on the result.
To explain a little further, an unsupported function will return a "magic" value which will eventually be replaced by `oldCalculatedValue` (or null if there is none). However, the magic value is not being propagated. In the issue, there are 3 places where this propagation is currently omitted - when performing a binary comparison, when evaluating the condition in the `IF` function, and when evaluating the `SUM` function. This PR causes propagation to happen in all of those places, and a few others (MIN, MINA, MAX, MAXA, ROWS, COLUMNS). I would not be surprised to have missed one or more of the other situations.
oleibman