fixbug：

	修复 “系统默认的变量”会覆盖掉“custom设置的变量”的bug

streamingpro-mlsql/src/main/java/streaming/dsl/template/TemplateMerge.scala

@@ -18,7 +18,7 @@ object TemplateMerge {
       "tomorrow" -> DateTime.now().plusDays(1).toString(dformat),
       "theDayBeforeYesterday" -> DateTime.now().minusDays(2).toString(dformat)
     )
-    val newRoot = root ++ predified_variables
+    val newRoot = predified_variables ++ root
 
     RenderEngine.render(sql, newRoot)
   }

streamingpro-mlsql/src/test/scala/streaming/dsl/template/TemplateMergeSpec.scala

@@ -0,0 +1,14 @@
+package streaming.dsl.template
+
+import org.scalatest.{FlatSpec, Matchers}
+import streaming.core.NotToRunTag
+
+class TemplateMergeSpec extends FlatSpec with Matchers {
+
+
+  "template merge" should "work" taggedAs (NotToRunTag) in {
+    val sql = TemplateMerge.merge("${yesterday}",Map[String,String]("yesterday"->"2017-03-01"))
+    assume(sql == "2017-03-01")
+  }
+
+}