Recommendation is to avoid using the year nomenclature as this
information is already encoded in the git repo. Avoids needing to
repeatly update.
Also updates AUTHORS.txt from current repo with contributor names
CHANGED: The text variable ${SHEETNAME} now always represents the name of the
sheet when used anywhere in the schematic editor, including the title block
ADDED: A new text variable ${SHEETPATH} which is replaced with the path to the
current sheet - e.g. "/Sheet 1/Sheet 2".
To ensure backward compatibility, the default drawing sheet now uses
${SHEETPATH}. Custom drawing sheets will need to be manually edited.
