Tuples - Add fst, snd functions to extract values

[gregberns]

Haskell has Tuple functions fst, snd to extract the first and second values from the tuple. I'm not seeing it in the docs.

Signatures:

fst :: (a,b) -> a

snd :: (a,b) -> b

Would probably want to add it to all the tuple types: Tuple3.third :: (a,b,c) -> c

[jihchi]

It is built-in in ReasonML, see the doc.

[gregberns]

Duh ... silly me. Any thoughts on adding third, fourth, etc for the tuple variations?

[johnhaley81]

Looks like this was done in #305