Rename helper method to placate IntelliJ 13
Use TypeTokens to define ConfigKeys in DynamicCluster

Removes some warnings. And remove some unnecessary casts.
Adds $brooklyn:entitySpec YAML function

Use to create EntitySpec instances from YAML, e.g. for cluster
member specs.
Merge pull request #1213 from sjcorbett/yaml-cluster-member-spec

Cluster member specs in YAML