updated TODO
fixed import bug in Complexity
fixed hashbang line
fixed boundary handling in Head
fixed boundary handling in Tail
fixed special cases in Sample
fixed meaningless usage of --numeric in Sort
fixed help on no argumets
Complexity: execption handling, TAB output
fixed bug in Head and Tail
added positive_int and counting_number types to parsers
added error handling function
refactored parse
release 1.8.2