Some useless code in previous commit
Make it impossible to de-select items in the listViewSmartScripts (so now you always have a line selected)
When the last line was deleted in the listview, we DO de-select everything and reset all fields
When creating a new line we also automatically select and load it
Also set the visibility of the Y, Z and O fields in SetVisibilityOfAllParamButtons
Set the default value of the script id (smart_scripts.id) field to -1 instead of 0; the value 0 is used in scripts so might cause confusion
Change the 'Exit' shortcut from Shift + F5 to Alt + F4
Pressing Enter in the SingleSelectForm now acts the same as double-clicking an item