Can react (not correctly yet) to command line arguments

refs #9
implemented basic checking for n and k

refs #9
splitting: implemented error in opening input file

refs #9
split: added checks for argument number.

refs #9
splitting: added lexical casting for n and k, and corresponding error handling

refs #9
splitting: fixed typo in catching bad_lexical_cast
implemented reconstructSecretFile with only 2 inputs:
[original file name (and path to the shares)]
and [output file name (and path)]
ref #9 #4
Merge branch '#9-CommandLineParsing'