Bump gradle to 2.13.

Author: nedtwigg

gradle/wrapper/gradle-wrapper.jar

@@ -1,6 +1,6 @@
-#Wed Apr 06 01:12:00 PDT 2016
+#Sat Jun 04 11:34:55 PDT 2016
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-2.12-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-2.13-bin.zip

gradle/wrapper/gradle-wrapper.properties

@@ -46,7 +46,7 @@ echo location of your Java installation.
 goto fail
 
 :init
-@rem Get command-line arguments, handling Windowz variants
+@rem Get command-line arguments, handling Windows variants
 
 if not "%OS%" == "Windows_NT" goto win9xME_args
 if "%@eval[2+2]" == "4" goto 4NT_args