- Ensure that JAVA_HOME variable actually referes to the JAVA_HOME
  rather than the path to the java runtime environment
Allow autocompletion for specifying path to JAVA_HOME through console
installation.
Initial refactor of JDKPathConsolePanel.
Reason for this is to sync functionality between GUI and Console version
of the JDKPathPanel.
Cleanup of intial refactor of the JDKPathConsolePanel
Synchronizing JDKPathPanel with JDKPathPanelConsolePanel through
HDJPathPanelHelper
Console mode of JDKPathPanel should also skip if was set ot skip panel.
Actually check that path is valid when thinking of skipping the panel.
- Centralize error messages
- Centralize validation
- Fix bug where I was saving JAVA_HOME into the wrong variable key
Merge branch 'master' into IZPACK-1147
Merge pull request #252 from mtjandra/IZPACK-1147

[IZPACK-1147] - Fixes for JDKPathPanel