Upgrade to Gradle 2.12

Issue: SPR-14048

gradle/wrapper/gradle-wrapper.properties

-#Mon Dec 21 23:01:07 CET 2015
+#Mon Mar 14 14:42:52 CET 2016
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-2.10-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-2.12-bin.zip

gradlew.bat

@@ -47,7 +47,7 @@ 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