Allow using absolute paths in parameters

[flaviut]

The parameter parsing code tries to parse "/foo" as an option, instead of as a path.

This appears to be for a seamless appearance in windows environments. Since this isn't documented anywhere (and since I think window's option syntax is stupid), I'd like to remove this.

[steveschnepp]

IMHO a better addition would be to leverage the quasi standard way to end parameters : --

This would mean that you can leverage absolute paths with:

 ./emu -opt1 /opt2 -- /absolute/path.ihx

Which solves both sides.