Report syntax errors in JavaScript code to help troubleshooting

Similar to #5, but for syntax errors in JavaScript.

- JavaScript

```
require-lint --pkg test/bad-syntax/package.json --src index.js

/Users/Romain/Documents/dev/require-lint/test/bad-syntax/index.js:4: Unexpected token )
    at throwError (/Users/Romain/Documents/dev/require-lint/node_modules/detective/node_modules/esprima-fb/esprima.js:2154:21)
    at throwUnexpected (/Users/Romain/Documents/dev/require-lint/node_modules/detective/node_modules/esprima-fb/esprima.js:2216:9)
```

- CoffeeScript

```
require-lint --pkg test/bad-syntax/package.json --require "coffee-script/register" --src index.coffee

/Users/Romain/Documents/dev/require-lint/test/bad-syntax/index.coffee:3:10: error: unmatched )
test = ()) ->
         ^
```