refextract: Addition of author replication for IBID's

• Implemented author duplication for titles marked as IBID's
• Improved the main author regex (added apostrophe between surname and surname prefix)
• Removed the dependency on letter case when matching authors taken from the author knowledge base
• Added configuration variables for author tags, for new 'title-ibid' tags, and for heuristic values (length of misc text deemed to be 'useful' within a citation ...)
• Removed any persisting print statements
• Improved comments, notably for the function which generates the author regular expression