Enhance compile-time and run-time error-trapping of size mismatches for assignment operator

[perrydv]

This aims to fix #1425 .

It puts a bunch of new logic in sizeAssignAfterRecursing to catch compile-time and run-time mismatches when a vector or matrix with indexing on the LHS is assigned from another vector or matrix. All the new logic is behind a new nimbleOption so it can be toggled off if it ever causes problems. There is a very real possibility that this will break something in testing as assignment processing is pervasive.

[paciorek]

We think this is basically good to go (test failures look unrelated) but decided to leave out of 1.2.0 in last push to release.

[paciorek]

@perrydv well we don't have much time before 1.2.1 release, but perhaps this is the time to do this? Given it's a minor release we won't be strongly encouraging folks to upgrade.

@perrydv @danielturek any thoughts?

[danielturek]

@paciorek Given that (a) it's a minor release, (b) this is protected behind an option, and (c) this is a useful improvement, I would vote to include it.

Furthermore, it's easier now to include it for 1.2.1, then if problems arise, fix (or remove) it for 1.3.0. But it's more annoying if it causes problems in an initial 1.3.0 release.

That said, I defer to either of you.

[paciorek]

Yes, that was my thinking regarding doing now vs. 1.3.0. I'll proceed with this.

[perrydv]

I'm ok with the decision here.