Add @InjectViews annotation for collection fields.

This also adds a specialized `ViewBag` type for being able to quickly apply properties or actions across all contained views.

TODO:
 * [ ] Forbid `null` from the `finder` when assembling views.
 * [ ] Fail fast if both `@InjectView` and `@InjectViews` annotation is present on a field.
 * [ ] `ViewBag` javadoc.
 * [ ] Simple `ViewBag` tests for each `apply` variant.

Closes #118.