MetricPrefixStr - Print SI Prefix Formatted Numbers

Author: Damon Bradley
Purpose: Print out formatted string using SI prefixes to clean up plots
for quantities in the thousands, millions, billions and trillions. This is useful for
publication-quality plots.

Version 1.0, March 28, 2013

INPUTS: xtickvec - Any vector of numbers
OUTPUTS: str - An array of strings with properly formatted numbers

USAGE EXAMPLE:

labels = MetricPrefixStr([1 10 100 33.64 1000 2000 40000 340000 7000000 1e14])

labels =

'1' '10' '100' '33.64' '1k' '2k' '40k' '340k' '7M' '100T'

class labels

ans =

char