Implement float math functions for two arrays

[Waterdragen]

Rationale

Since we have something like array.binary_fn(float), we could also have array.binary_fn(array).
Extends functionality of #1042 and #1507

New binary methods for RHS = float

• atan2

New binary methods for RHS = arrays

• powi_all
• powf_all
• log_all
• abs_sub_all
• hypot_all
• atan2_all

[nilgoyette]

Can you please add one test for at least one of those functions?

[Waterdragen]

Hi there! I've added a test for hypot_all. I've also added tests for boolean, unary, and binary ops for #1042.

[nilgoyette]

LGTM. I'll leave time for the other maintainers to react, if need be, then I'll merge.

[akern40]

I'm not sure this is the right approach here. If we grant that we want this (and I think we do?) I'd rather we take advantage of generics and traits to make it happen. I had a working example at #1469 of what this might look like.

We also should consider whether a method like this should perform broadcasting for the user or not.