[build] the build can now autoclean

autocleaning means that the build system detects that the usual incremental mode,
where the build artefacts are not deleted and instead used to skip steps already performed,
is not an option due to changes in the build script itself or a change in deps not detectable.

It works by having a version number which can be incremented, and a system that checks
for mismatches and forces a clean.

buildScripts/maven.ant.xml

@@ -59,7 +59,7 @@ This buildfile is part of projectlombok.org. It makes maven-compatible repositor
 		</sequential>
 	</macrodef>
 	
-	<target name="maven" depends="version, dist, javadoc.build" description="Creates a maven repo for the current release into a build dir. The intent is for you to put that on a server someplace. Will invoke your local mvn installation.">
+	<target name="maven" depends="version, dist, javadoc.build, -setup.build" description="Creates a maven repo for the current release into a build dir. The intent is for you to put that on a server someplace. Will invoke your local mvn installation.">
 		<mkdir dir="build" />
 		<mkdir dir="dist" />