add applyOptional
clarify readme
Update README to remove reference to Intro module

Closes #90
Merge pull request #91 from dtchepak/patch-1

Update README to remove reference to Intro module
Removing answer for reverse from List.hs
Removing answer for reverse from List.hs
Removing an errant Monad from Apply.hs
Merge pull request #93 from dtchepak/patch-3

Removing an errant Monad from Apply.hs
Merge pull request #92 from dtchepak/patch-2

Removing answer for reverse from List.hs
Allow do-notation in JsonParser
Point students to json.org for control chars
Fix control character test case
Don't suggest betweenCharTok for jsonString

`betweenCharTok` will produce an incorrect solution for `jsonString`,
because it would drop spaces after the opening quote.
Merge pull request #95 from bts/json-parser-fixes

JsonParser improvements
clarify help links
Merge branch 'master' of github.com:NICTA/course
merge