Support Groovy Markup templating in Spring MVC

This commit adds support for Groovy templating, available as of
Groovy 2.3.0 (and 2.3.1 for advanced use cases, such as layouts and
fragments).

To enable this, one should create a new GroovyTemplateViewResolver
Bean in her application.

Issue: SPR-11789
Polish tests

Add array type information.