1. Changed reference from foldr to foldl in foldr.js's comments.
2. Added an explanation of internal to CONTRIBUTE.md
.

Reviewed by @tolmasky.
Fix grammar, add Note about dist/ramda.js being generated.

Reviewed by @tolmasky.
Merge pull request #678 from tolmasky/docs

Some comment changes
rename R.invokerN
Merge pull request #679 from davidchambers/invoker

rename R.invokerN