Port reverse-string from javascript track

[gavinhenderson]

A port of the JS 'reverse-string' challenge as requested in #417

Things I did to port:

• Converted it to test
• Added exercise to config.json and change its UUID
• Updated tests and example to match new linter
• Copy ecmascript setup,requirements and making the test suite pass sections into exercise README.md

[matthewmorgan]

@gavinhenderson thanks for taking this on!

Looks like the build is failing, and we would like you to update the instructions even though the changes there will presumably be changed again by the migration script.

Exercise update looks fine to me though-- when you get your updates I will pull and check it out locally.

[matthewmorgan]

You'll want to update these references so the point to the EcmaScript track for now. We'll need to handle converting them (finally) to JavaScript in the migration.

[matthewmorgan]

Again, these should be updated to match the ES setup/test suite instructions. Same goes for the rest of the instructions here.

[matthewmorgan]

Looks like you'll need to change the UUID. Travis says they need to be unique across tracks, so the build is failing:

-> The following UUID was found in multiple Exercism tracks. Each exercise UUID must be unique across tracks.

[gavinhenderson]

@matthewmorgan Thats the changes made

[matthewmorgan]

@gavinhenderson Thanks! 1 down, 5 to go...