ramda: Error checking

@buzzdecafe Commented on a now outdated diff in #464

now we expect the user to pass in the right stuff without us enforcing it. e.g. we don’t check the fn passed to map, foldl, etc.

After some real world use of ramda, my stance is that I don’t agree with this. If any of the functions in ramda is used on its own then yes, type checking is probably not needed. But when combining several functions with compose, useWith or just inlining calls to them, errors can happen pretty easily and the stack trace can be a bit cryptic. I think that if users received messages like

R.map expects the first argument to be a function but actually got the string "foo"

it would be yet another reason to love this lib.

I think it would be easy to create a single internal function that does error checking and produces well formatted error messages if anything is wrong.

If this seems like a good idea then I am happy to investigate how this feature could be added with and input to functions validated with minimal effort.