Clean release notes and welcome message for 6.4
Clean release notes and welcome message for 6.4

gradle/gradle,blindpirate/gradle,blindpirate/gradle,gradle/gradle,gradle/gradle,gradle/gradle,blindpirate/gradle,gradle/gradle,blindpirate/gradle,blindpirate/gradle,gradle/gradle,gradle/gradle,blindpirate/gradle,gradle/gradle,gradle/gradle,gradle/gradle,blindpirate/gradle,blindpirate/gradle,blindpirate/gradle,blindpirate/gradle