* Convert Eeschema from manually linked list to DLIST for storing
SCH_ITEM objects.
* Add helper functions to SCH_SCREEN for appending list of SCH_ITEM
objects.
* Fix bug in wire editing code for accurate undo/redo behavior.
* Add member to DLIST to append another DLIST.
* Other minor code cleaning.
* Correct all user strings and comments for the correct capitalization of
application names according to JP. They are KiCad, Pcbnew, CvPcb,
Eeschema, and GerbView.
* Add a note the the user interface policy about the correct capitalization.