added java friendly type converter per #588

modules/swagger-core/src/main/scala/com/wordnik/swagger/converter/TypeConverter.scala

@@ -0,0 +1,19 @@
+package com.wordnik.swagger.converter
+
+import scala.collection.mutable.HashMap
+
+class TypeConverter extends ModelConverter with BaseConverter {
+  private val LOGGER = LoggerFactory.getLogger(this.getClass)
+
+  val m = new HashMap[String, String]
+
+  def read(cls: Class[_], typeMap: Map[String, String]): Option[Model] = None
+  def add(sourceClassName: String, destClassName: String) = {
+    m += sourceClassName.toLower -> destClassName
+  }
+
+  override def typeMap = m.toMap
+
+  // don't expand mapped models
+  override def ignoredClasses: Set[String] = m.keys.toSet
+}