Various minor new features, improvements and bugfixes.

• --dedup n removes duplicate triples in a window of size n
• --write-base adds @base to Turtle output
• Ignore cells containing only whitespace
• Improved handling of unusual characters in header row
• Automatically pre-define the apf: prefix for apf:strSplit
• Upgrade Jena to 3.11.0 and OpenCSV to 4.6

Various minor new features, improvements and bugfixes.

• Upgrade from Jena 2 to Jena 3.1.1
• Add tarql:expandPrefix and tarql:expandPrefixedName functions
• Better handling of stray quotes that are misinterpreted as starting a multi-line field (#10)
• Handle question marks in column headers
• Allow --quotechar none (#10)
• Recognize tab, singlequote, backslash etc. as values for --delimiter, --quotechar, --escapechar
• Add --base argument (#20)
• Ensure rdf: prefix is always registered when writing Turtle (#36)
• Add --stdin option to read input from STDIN (#21)
• Generally show just error message instead of stack trace (#38)