Create library of common operators

[EntilZha]

There are quite a few of common operators which are passed into functions such as map/filter/reduce. It might be a good idea to compile a library of common operators in functional.ops.

[adrian17]

Note that operator module already provides some insitric-like ready to use operators:

seq(range(1000)).fold_left(0, operator.mul)

If the ops module is going to happen, it could just be started with from operator import * so they can be instantly used from there.

[EntilZha]

Great idea, I didn't even know that existed.

[EntilZha]

I think the better place for this is to give examples in the docs of using this. Probably better to promote composing different modules/packages together than a single monolithic thing. If there are a set of very common and helpful operators, then it might make sense to add them.