Add change location support

Based on this question https://github.com/caelum/vraptor-i18n/issues/1 PR creates the initial internationalization support via jstl.

You can disable the environment via two features, which are:
  - Setting via parameter (_locale), default true
  - Setting via web browser, default false

I used an interceptor because extending the RequestHandlerObserver will broke applications that extend it.

I did not do the issue of validate if has the resource of language because in testing, I realized that Java uses the default if not valid and need help if necessary, I don't know the best way to get this information from vraptor.

I'm waiting any suggestions to improve the code quality.
The Locale from Browser only work if enabled on Environment and is null on session.
So, the Request Parameter will be configured.
https://github.com/dtelaroli/vraptor-i18n/blob/f81c13f44e3316c9254f54806300bc74538bb0e5/src/main/java/br/com/caelum/vraptor/i18n/LocaleInterceptor.java#L36