Add "Arrow Functions, part 1" exercise.
0.3.0
Add default arguments exercise.
Add default arguments part 2 exercise.
0.4.0
Fix misnamed variables in rest solution.
Make arrow functions output easier.

People did *not* like having to do `["${inputs.join('", "')}"]`.
Minor tweaks to template string instructions.
Note that you need a module for default arguments part 2.
Clarify default arguments part 2 transform example a bit.
0.4.1
Show Traceur compilation errors.

Turns out my main problem was using `error` when it should be `errors`.
0.4.2
Use arrow functions in rest solution.
0.4.3
Fix horrible bug that caused a blank error when doing anything.
0.4.4
Make output formatting on spread solution less onerous.

Yet again, people really dislike having to use `.join`.
A few copy updates and fixes for clarity and edification.
Add a hint about using .replace to tagged template strings.