Upgrade sbt to 0.13.13

Atry · web-flow · commit b38ec45b3113 · 2016-10-12T18:52:41.000+08:00
diff --git a/project/build.properties b/project/build.properties
@@ -1 +1 @@
-sbt.version=0.13.11
+sbt.version=0.13.13
