Adding missing TreePacksPanel.headline string
Merge branch 'IZPACK-1071' of https://github.com/mtjandra/izpack into mtjandra-IZPACK-1071

Conflicts:
	izpack-core/src/main/resources/com/izforge/izpack/bin/langpacks/installer/spa.xml
Merge branch 'mtjandra-IZPACK-1071'