Not working on node 0.12

Nobody has claimed this yet.

This library is amazing.

However, I see you used:

```
var NODE_REPL_LOOP = (function * () {
^
```

And i get this error:

```
/Users/mozilla/Proj/schemas/index.js:46
var NODE_REPL_LOOP = (function * () {
^
SyntaxError: Unexpected token *
at exports.runInThisContext (vm.js:73:16)
at Module._compile (module.js:443:25)
at Object.require.extensions..js (/usr/local/lib/node_modules/node-repl/bin.js:19:10)
at Module.load (module.js:355:32)
at Function.Module._load (module.js:310:12)
at Module.require (module.js:365:17)
at require (module.js:384:17)
at Object. (/usr/local/lib/node_modules/node-repl/bin.js:22:1)
at Module._compile (module.js:460:26)
at Object.Module._extensions..js (module.js:478:10)
```

Maybe you want to specify some flags to use / node version?

Start at index.js line 46 and compare the generator syntax with the repository's stated Node 0.12/iojs-and-above support. Reproduce the reported SyntaxError under Node 0.12, then verify whether the library runs on the claimed version or whether the supported version or required flags need to be documented; done means the compatibility behavior is clear and verified.

Written by the indexing model from the issue text.