Fix issue #1429665 (eeschema doesn't recognize .sch file when the LIBS section is empty. But the section is not used, just a comment, therefore can be empty).
Very minor other fixes.

Update ecc83 demo. default KISYS3DMOD definition on Linux: add /usr/local/kicad/share/kicad/module/package3d test to find a suitable value.

   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.

AUTHORS.txt: add some contributor names (I certainly forgot some other contributors, and I apologize).
Demos: convert .brd files to .kicad_pcb files and fix 2 broken files