Rename map to fmap

[gyzerok]

What do you think about renaming map to fmap for functors. So we can eliminate confusion in this. The point is that map usually used to map collections, not single values.

[zerkms]

I've had similar thoughts after a friend of mine asked me how to distinguish between a map and a map

[DrBoolean]

I wholeheartedly subscribe to https://github.com/fantasyland/fantasy-land as the official JS spec for this stuff. If we want to rename it, we should ask them there.