Replaced the set of (ancient) arrays used for saving/restoring lines of

terminal text and attributes with a linked-list. In doing so:
- the save depth is no longer fixed (at 4), but dynamic and unbounded
- the current column position is also saved/restored (bug fix)
- no more copy/pasta from sbbsdefs.h into js_console.cpp
- the JS console.saveline() and restore() methods now return Bool to indicate
  success/failure

Also, some trailing white-space was auto-removed due to local editor settings.