* Derive SCH_SHEET_LIST from std::vector rather than using internal array
management. Change all internal code to use iterators or array operator
in loops.
* Allow creation of empty SCH_SHEET_LIST for external population for plotting
and printing.
* Clean up print an plot code to take advantage of new SCH_SHEET_LIST behavior.
* Make BuildSheetList() public so list can be populated after creation.
* Update all instances of SCH_SHEET_LIST with the appropriate SCH_SHEET
object on initialization.
* Create const and non-const version of SCH_SHEET_PATH::GetSheet().
* Uncouple SCH_COMPONENT::GetRef() from SCH_SHEET_PATH and use SCH_SHEET
instead.
* Uncouple SCH_COMPONENT::GetUnitSelection() from SCH_SHEET_PATH and use
SCH_SHEET instead.
* Fix all calls to GetRef() and GetUnitSelection() to pass a pointer to the
appropriate SCH_SHEET object instead of an SCH_SHEET_PATH object.
* Remove global s_NetObjectslist.
* Separate out non-owning version of NETLIST_OBJECTS_LIST into NETLIST_OBJECTS.
* Fix double free pertaining to ~NETLIST_READER().
* Remove all file-io from CvPCB.
* Remove exe launcher cvpcb, retain only cvpcb.kiface, since cvpcb.kiface has no file i/o.
* Add void CVPCB_MAINFRAME::KiwayMailIn( KIWAY_EXPRESS& mail ) and teach it to use old
netlist loading code with a STRING_LINE_READER LINE_READER.
* Fix BEGIN_EVENT_TABLE( CVPCB_MAINFRAME, KIWAY_PLAYER )