Use # instead of = for ps2pdf options in Windows.

I couldn't get pstool to work under windows, because ps2pdf would fail with the error message: "**** Unable to open the initial device, quitting." Subsequently pdfcrop would also fail because its input file does not exist.

I eventually found this: http://ghostscript.com/doc/7.07/Use.htm#MS_Windows recommending the use of '#' instead of '=' for passing options to ghostscript via ps2pdf. Making this change and removing the quotes around the options for ps2pdf fixed the problem.