In-place division/multiplication by scalar, closes #20

[edubart]

This also introduces the fmap_inplace function which is used to implement those operations.

[mratsim]

For the inplace map/fmap I was thinking of using apply as a name but I'm still confused between apply and applymap as it's commonly used in other data science package (pandas ...).

I'll sleep on it. In any case, fmap_in_place is so descriptive that it won't be a problem to release it and eventually deprecate it.

[mratsim]

To stay consistent with Nim's sequtils can you rename fmap_in_place to apply?

Thanks.

[edubart]

Renamed to apply.

[mratsim]

Great, thanks