Resolve "Create new make target sync_xlsx"

Closes #16 (closed)

Added the following scripts:

• tsv2xlsx.py
• xlsx2tsv.py (replaces xlsx.py)
• sort-templates.py

Modified cpont.Makefile by:

• adding sync_xlsx target
  • creates cpont.xlsx from the template tsv files
• replacing xlsx target with update_tsv target
  • creates template tsv files from cpont.xlsx and sorts the tsv contents by the ID field
  • the sort outputs warning messages for duplicate IDs