BugFix: Fix 2 new/modified slot_ funct'ns to use passed args not globals.

Though presently the argument supplied to the modified/renamed icon size
setting: dlgTriggerEditor::slot_setToolbarIconSize( int ) and the new:
dlgTriggerEditor::slot_setTreeWidgetIconSize( int ) ARE the globals
used to store this information, this is not implicit in their declared
purpose, so it is best to actually use the supplied value!

Signed-off-by: Stephen Lyons <slysven@virginmedia.com>