Update gradle to 2.11.

This fixes issues downloading from dmdirc.com over SSL, as
previous versions of gradle didn't support SNI.

build.gradle

@@ -12,6 +12,6 @@ tasks.dependencies.dependsOn subprojects*.tasks.dependencies
 
 task createWrapper(type: Wrapper) {
     description 'Downloads and installs an up-to-date wrapper for gradle.'
-    gradleVersion = '2.10'
+    gradleVersion = '2.11'
 }
 

gradle/wrapper/gradle-wrapper.properties

@@ -1,6 +1,6 @@
-#Wed Feb 03 19:23:01 GMT 2016
+#Sun Feb 21 16:52:42 GMT 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-2.11-bin.zip