Added import mapping for Timestamp

Author: Ganesh Subramanian

src/main/scala/com/wordnik/swagger/codegen/BasicJavaGenerator.scala

@@ -84,6 +84,7 @@ class BasicJavaGenerator extends BasicGenerator {
   override def importMapping = Map(
     "File" -> "java.io.File",
     "Date" -> "java.util.Date",
+    "Timestamp" -> "java.sql.Timestamp",
     "Array" -> "java.util.*",
     "ArrayList" -> "java.util.*",
     "List" -> "java.util.*",

src/test/scala/BasicJavaGeneratorTest.scala

@@ -123,6 +123,8 @@ class BasicJavaGeneratorTest extends FlatSpec with ShouldMatchers {
   it should "honor the import mapping" in {
   	config.importMapping("Date") should be ("java.util.Date")
   	config.importMapping("DateTime") should be ("org.joda.time.*")
+  	config.importMapping("TimeStamp") should be ("java.sql.Timestamp")
+  	config.importMapping("Set") should be ("java.util.*")
   }
 
   /*