docs: correct documentation for buildscript block, add local confirmProjectVersionIncrementedTask

Small fix to correct the example provided in the README.

Also includes a way to invoke the confirmProjectVersionIncrementedTask, sharing the logic with the task in the release.

gradle/wrapper/gradle-wrapper.properties

-#Fri Aug 26 09:10:13 CDT 2016
+#Tue Aug 30 12:39:17 CDT 2016
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-3.0-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-3.0-all.zip