[IZPACK-794] Pressing "Generating automatic installation script" throws java.lang.NoClassDefFoundError: com/izforge/izpack/panels/imgpacks/ImgPacksPanelAutomationHelper -- post-fix for TreePacksPanel
Merge pull request #224 from rkrell/IZPACK-794

[IZPACK-794] Pressing "Generating automatic installation script" throws java.lang.NoClassDefFoundError: com/izforge/izpack/panels/imgpacks/ImgPacksPanelAutomationHelper