Cvpcb: Add a tool to solve conflict assignments when the schematic netlist and the .cmp file do not contain the same assignment and both are valid fpid.
It happens when footprint assignments are modified outside Cvpcb (when editing the footprint assignment field in schematic)

   To use multiple working threads.  This entailed adding KiCad typedefs:
*) Add typedefs for MUTEX and MUTLOCK which mask the actual choices for the project.
*) Add FOOTPRINT_LIST::DisplayErrors( wxWindow* ) which is a single strategy for
   showing aggregated load errors.  Although what's there is only scaffolding
   and needs a volunteer who knows HTML pretty well.
*) Ensure all callers of ReadFootprintFiles() use the new DisplayErrors() function.   
*) Push utf8.cpp and utf8.h into common library for open use.

Pcbnew: netlist dialog: add silent mode option, and tool tip to the 2 options (dry run and silent mode)
dialog_display_info_HTML_base: derived now from dialog_shim.

   File "rules" has instructional text as comments near top.

2) Convert all text files in repo to LF line ending form.
   Any checkout done with "rules" in play will convert the working
   tree to native line ending, while keeping repo as LF line ending.

fctsys.h: remove useless define.
Fix minor issues and add minor enhancements.

Speed up DIALOG_LOAD_ERROR::ListSet(), used to display lists of errors ( up to 100 x faster) in DRC or loading lib errors