Comment 4 for bug 195220

Migration completed. I'm not 100% sure about removing fixupSingleFilename(), replaceArgs() and related cruft, though I think it's no longer necessary, because Glib takes care of all that. I changed the LANG variable to a different encoding and everything seemed to be OK. However, I haven't tested on Windows.

Important changes:
- Many things refactored: killed sp_process_args(), sp_common_main() and the argument enum, removed the strcmp monstrosity that determined whether to use the GUI, etc.
- Standard GTK options are now accepted.
- Options put into groups.
- Moved print-something-and-exit cases from sp_process_args() to main()
- And of course removed popt dependency.

Regressions:
- Long option descriptions not aligned neatly like with popt. This is not yet implemented in Glib.
- Unsure about how filenames with non-ASCII characters will behave on Windows

Remaining work:
- Move command-line operations into a separate file.
- Move all option-related stuff, including the global variables, into a new class.
- Allow to work one more than one file in a single invocation, i.e. "inkscape --file=test.svg --export-pdf=a.pdf --export-eps=a.eps --file=test2.svg --export-pdf=b.pdf"
- Make --verb and --select options work while --without-gui (doesn't work in current SVN)