Fuck yeah!

* Feature complete and working:
** User prompted whether to edit challenge's parameters (defaulting to no)
** If user edits parameters, user input is validated
** Challenge array created in background, user prompted to print result to file (defaulting to no)
** If user chooses to export result to file, path is validated to be writeable before writing in an OS-agnostic way
** If path is un-writeable, user is prompted to enter a valid one (defaulting to <present working directory>/fizzbuzz.txt)