a tiny cli calendar

EXAMPLE
	ncal -b
		print current month in horizontal format, highlighting today
	ncal -bMw3
		horizontal, week starts on Monday, week numbers, current month +-1
	ncal -bMw3A 3
		like above, but adding an additional 3 months to the output
	ncal -bMwy 2019
		outputting all months in 2019

FLAGS
	-b	print in horizontal format (weeks go from left to right)
	-M	a week starts on Monday
	-w	add week numbers to the output
	-3	print the previous, the current and the coming month
	-A	add an additional number of months
	-y	specify a year to output
