Rename serve_static_assets to serve_static_files.
Fix Definition#name to convert @options[:as] to string

In case define property with `as` and `selectable`
options:

```
property :first_name, as: :name, selectable: true
```

Representer#handle_definition? returns false
because `@options[:as]` is a Symbol and selector keeps
their keys as String.
Remove serve_static_files(assets) from test config.

Default value of config.serve_static_files(assets) is `true`.
Fix comment
Reproduce property option bug

Can't work with selector when `as` and `selectable` were passed to
`property` method.
Merge pull request #14 from yui-knk/fix/space

Remove a blank
Merge pull request #13 from yui-knk/fix/representer

Fix Representer::Definition#name to always return as string
Merge pull request #12 from yui-knk/fix/environments

Rename serve_static_assets to serve_static_files.
Merge pull request #15 from yui-knk/fix/typo

[ci skip] Fix comment
Remove space