Support command-line arguments

[switch-blade-stuff]

Hello, I have been working on a mapping project, and frequently needed to create a series of projections at a time. This has been somewhat tedious since all of the options need to be specified by hand through the interactive interface and cannot be automated.

I have implemented a headless interface that takes the projection options from command-line arguments. When no arguments are specified, it will fall back to the existing interactive interface.

[hersfeldtn]

The main function is designed to be callable as a python function, e.g. here's a script I use to project out from a global equirectangular map to several recentered hammer maps:

import projectionpasta as proj

infile = 'grey_1.png'
outfile = 'grey2'
interp = 2

proj.MainDeg(infile, outfile+'_C.png', 0, 3, 0, 0, 0, -10, -20, 0, interp=interp)
proj.MainDeg(infile, outfile+'_NE.png', 0, 3, 0, 0, 0, 60, 30, 0, interp=interp)
proj.MainDeg(infile, outfile+'_E.png', 0, 3, 0, 0, 0, 140, 10, 0, interp=interp)
proj.MainDeg(infile, outfile+'_W.png', 0, 3, 0, 0, 0, -120, 10, 0, interp=interp)
proj.MainDeg(infile, outfile+'_S.png', 0, 3, 0, 0, 0, 180, -50, 0, interp=interp)

Nevertheless this is easy enough to fold into the next update, whenever I do one.