Add a few more F# style functions

[adamklein]

I think we should reveal all the functions from Series.fs section Accessors and slicing?

• [ ] Series.before
• [ ] Series.after
• [ ] Series.getSubRange

Perhaps analogs for Frame rows?

• [ ] Frame.rowsBefore
• [ ] Frame.rowsAfter
• [ ] Frame.rowsGetSubRange

... etc

[EDIT: only those that I don't think can be represented using natural F# slicing notation.]

[evilpepperman]

+1 It's irksome to mix |> and member styles at times.

[tpetricek]

This is certainly a planned feature! I'll look into this after we release the next version (it is just adding new functions, so not a breaking change and so it should be easy to add in a minor revision).