Update to Dropwizard 0.7.0-rc2
Add validation support for Scala Collections

Also supports validation of case classes, via the constraints in
`io.dropwizard.scala.validation.constraints`.
Include validations in core bundle
Flesh out ScalaValidatorsSpec

Demonstrate that Min/Max, DecimalMin/DecimalMax work as expected for
scala's numeric types.
Add basic integration test for module

Currently tests validation for collections and partially tests Jersey
support.