Author: Doug Jacobsen
Date: 02/12/13

About:
	This script is used to compute quality metrics on an MPAS mesh.
	It appends to the grid file four arrays.
		cellQuality
		triangleQuality
		triangleAngleQuality
		obtuseTriangle
	
	In addition, it writes histgrams to a file named quality.png, and potentially displays them.

	The usage statement can be seen with ./grid_quality.py -h, but is as follows.

Usage: grid_quality.py [options]

Options:
  -h, --help            show this help message and exit
  -f FILE, --file=FILE  Path to grid file
  -b NUMBINS, --bins=NUMBINS
                        Number of bins for histogram
  -q, --quiet           Turns off display of plots, though they are still
                        saved in quality.png

