Created Makefile
Updated Makefile

Added the ability to compile each .icn file independently and link
them all together later to the makefile.
Updated .gitignore

Updated the .gitignore to include compiled but unlinked unicon
files (*.u)

Changed the name of the ignored final binary

Added data files (*.dat) to the ignore list
Created basic IO functions

Created readBoard() function, which is passed a filename and
returns a sudoku board read from that file.

Create printBoard() function, which prints a sudoku board to stdout.
Created main file

Created the main function, which will read in and print a board
from a file supplied as a command line argument
changed main logic
fixed io bugs
added solving functions
updated input cset

changed from manually listing digits to using the intersection of &digits
and '_'
Added check for failed solve
Merge branch 'develop'