Pass options to ps2pdf using -foo#bar instead of -foo=bar.

[anntzer]

The former works both on Windows and Linux (so we can stick to it)
whereas the later only works on Linux (so we had to use a switch
depending on the OS).

Will conflict #10294, but easy to resolve either...

Closes #10290

PR Summary

PR Checklist

• Has Pytest style unit tests
• Code is PEP 8 compliant
• New features are documented, with examples if plot related
• Documentation is sphinx and numpydoc compliant
• Added an entry to doc/users/next_whats_new/ if major new feature (follow instructions in README.rst there)
• Documented in doc/api/api_changes.rst if API changed in a backward-incompatible way

[jklymak]

.... add the autorotate thing and I'll close my PR if this works...

[jklymak]

-dAutoRotatePages#false

[anntzer]

done

[jklymak]

This worked on my machine w/ cde

import matplotlib
matplotlib.rcParams['ps.usedistiller'] = 'xpdf'

import matplotlib.pyplot as pl

f = pl.figure (figsize=(7,5))
ax = f.add_axes ([0.15,0.15,0.8,0.8])
ax.set_ylim (0., 1.)
ax.set_xlim (0., 1.)

ntext = 8 # this is the minimum number of calls to get rotation
ytext = 0.5
for i in range (ntext) :
    xtext = (1. / ntext) * i
    n = 'test{}'.format (i)
    ax.text (xtext, ytext, n, rotation='vertical')

f.savefig ('test.eps')

[dopplershift]

Pending CI...

[jklymak]

Well it works on linux, and it should be the same code on Windows, so I'll take a chance and merge it.