Implement GORM-style dynamic finders

[nealeu]

Spring Data Commons supports dynamic finders for extenders of Repository.

We should consider whether this is a valid goal for a simpler API.

The existing query infrasstructure via the com.wwm.expression package would probably be used under the hood.

See http://static.springsource.org/spring-data/data-jpa/docs/1.0.0.M1/reference/html/ for how it's used with JPA