Created a parameter for returning error code

[regebro]

Thanks, this looks good, but I think --check should suppress the output, since it's a check if there is a difference you don't want to deal with that output.

I also wonder if it doesn't make more sense to always return 1 when there is a difference, even without the --check parameter.

[Glamhoth]

I also wonder if it doesn't make more sense to always return 1 when there is a difference

I thought about it too, but I didn't want to change the default behavior. If someone is using xmldiff in their scrips/pipeline then such change could break them. I choose the --check parameter, especially after seeing your comment in #91.

but I think --check should suppress the output, since it's a check if there is a difference you don't want to deal with that output.

Actually printing output when there is a difference is quite useful (and diff does it that way). For example in my case, xmldiff is used in integration tests which are run on the CI. Output is handy to quickly see why given test failed. Suppressing output could be implemented by -q / --quiet parameter maybe?

[regebro]

OK, let's do it that way.

[Glamhoth]

@regebro conflicts are resolved

[regebro]

OK, I'll merge this.