Array sub-schema validation

Added test and code to validate array sub schemas. Here's the test to see the implementation: https://github.com/domharrington/schemata/blob/868701a7a6894e3d1d65c693058bb89b2520737c/test/schemata.test.js#L537-L562

Errors are added to the array index in the model where the error occurred. Is this okay?

Also:
- added 0.10 to travis.yml
- misc linting and whitespace