When last_version is deleted, do not delete text and previous versions in cascade, but really delete text only when there is no previous version, otherwise update text.last_version with previous version.
src.dir = src
lib.dir = lib
doc.dir = doc
build.dir = build
product.name = yuicompressor
version.number = 2.4.2
jar.name = ${product.name}-${version.number}.jar
dist.package.name = ${product.name}-${version.number}