Use child_process.spawn instead of child_process.fork

For whatever reason, using `child_process.fork` causes the following code / command combo to loop indefinitely:

__test.coffee:__
``` 
console.log "hey!"
MockApi = require 'mock-api-server`
api = new MockApi(port: 7000)
api.start()
```

__shell:__
```
$ node -e 'require("coffee-script-redux/register");require("test");'
hey!
hey!
hey!
hey!
```
(Fake API connections refuse)

But this works fine:
__shell:__
```
$ ./node_modules/coffee-script-redux/bin/coffee test.coffee
hey!
```
(Fake API connections return data)

I'm not familiar enough with the difference between `fork` and `spawn` to figure out what's going on. For now, this should fix any fake-api issues we're seeing.