Sadly, each unit of a component can have its own unique fields. This
change finds the last non blank field and records it. Last guy wins
and the order of units occuring in a schematic hierarchy is variable.
Therefore user is best off setting fields into only one unit. But this
scavenger algorithm will find any non blank fields in all units and use
the last non-blank field for each unique field name.
Fixes lp:1471417
https://bugs.launchpad.net/kicad/+bug/1471417
* 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 )