[IZPACK-1132] - Infinite loop fix

This is to address http://jira.codehaus.org/browse/IZPACK-1132
1. Fix infinite loop by adding checks
```
   if (initial)
    {
        if (checkValues[pos] != DESELECTED)
        {
            checkValues[pos] = DESELECTED;
            changes = true;
        }
    }
...
    if (checkValues[pos] != DEPENDENT_DESELECTED)
    {
        logger.fine("Pack" + packName + " cannot be installed");
        checkValues[pos] = DEPENDENT_DESELECTED;
        changes = true;
    }
```
2\. Ensure TreePacksPanel upates JTree to latest information on activation
3\. Add helper text to TreePacksConsolePanel to inform user when a pack is unselectable. (Not required and condition evaluates to false)