histo: Print out a crude histo

Usage: histo <options>

Options:
	-n	Number lines
	-m	Worry about memory
	-f <f>	Reduce by factor <f>
	-F	fill in missing values.  Only works for ints.
	-s <c>	Use symbol <c> for plot
	-w	Fill terminal width
	-b <n>	use integer bins <n>

Notes: