Adds the value of the bar on top of the bar for the active figure, ignoring
bars with a value of zero. Automatically pulls bar height data from the
figure. Accepts up to three variable arguments in any order:
rotation is the angle of the text (default zero)
textoption is the formatspec string (default '%.0f')
ignorezero is a logical indicating if bars with a value of zero are
labeled (default true)

Example usage:
bar([2 6 7])
h = barlabel
h =
Figure (1) with properties:
...

bar([3 98 65])
barlabel(false,45);
Labels all bars (including zeros) and rotates text 45 degrees