Adds @JsonProperty getter support in case classes

[rybosome]

Partially resolves #68

Adds support for @JsonProperty annotation on methods during serialization of case classes. If a method that takes no parameters is annotated with @JsonProperty("${name of property here}"), then its return value will be used rather than the native attribute. For instance:

case class Person(name: String) {

    @JsonProperty("name")
    def serializeName: String = name.reverse

}

[ghost]

This annotation is a must have to avoid reserved word issues in scala. Please merge