Several small improvements plus one bug fix

• Remembering Posn improved.
• Form is a bit taller now when Fire is started. Was too small.
• Ctrl+A now works in the "Search for" edit control and the hit list and in "Start looking here".
• Ctrl+C now works in the "Search for" edit control and in "Start looking here".
• "Select all" was removed from the "Edit" menu.
• Bug fix: in case Fire was installed in a non-default folder then none of the HTML files offered
  in the "Help" menu were found due to a missing folder separator.