change package name and sbt project name to rocket

rocket/src/main/scala/consts.scala

@@ -1,4 +1,4 @@
-package Top {
+package rocket
 
 import Chisel._
 import scala.math._
@@ -239,5 +239,3 @@ object Constants
   val VIMM_ALU = UFix(1, 1)
   val VIMM_X = UFix(0, 1)
 }
-
-}