Update required node version

Note: hapi requires node >= 0.10.22 since version 3.0.0

See also https://github.com/spumko/hapi/commit/7743419614d0c1b59f0c494acc1acab27234e956

Using node >= 0.10.22 solves also an issue occurring at server start:

```
hoodie-server/node_modules/hapi/lib/schema.js:182 expiresIn:
    Joi.number().xor('expiresAt'),

TypeError: Object [object Object] has no method 'xor'
```
Merge pull request #266 from potomak/update-node-version

Update required node version