Update problem.md

Added a paragraph about module "contract".
Reason: lots of questions on https://github.com/nodeschool/discussions about this exercise. Mostly missing the fact that you can't change the `ext` argument outside the module.
Merge pull request #95 from pirfalt/patch-1

Update problem.md
unify on "program.js" instead of "myprogram.js"
Merge pull request #97 from linclark/unify-file-naming

unify on "program.js" instead of "myprogram.js"
Update time server doc, indicate 24 hour time
Merge pull request #98 from jknipp/master

Update time server problem doc, indicate 24 hour time
Update problem.md

When we were doing this challenge it was unclear that the arguments had to be in exactly that order.
Update problem.md

So we were thinking that it might be easier to understand that you are suppose to call on on the stream.
Merge pull request #100 from Andersos/patch-2

Update problem.md
Update problem.md

Comma =)
Merge pull request #99 from Andersos/patch-1

Update problem.md
correct JSON.stringify() typo
Merge pull request #105 from ascott1/typo-fix

correct JSON.stringify() typo
increase http client chunk delay
Merge branch 'master' of github.com:rvagg/learnyounode
1.0.1
fixes nodeschool/discussion#356
Spelling error - Changed benifit to benefit
Merge pull request #109 from edasaur/master

Spelling error - Changed benifit to benefit
Fix exercise link format to be clickable in iTerm