Solve crash when trying to show error with bad separator.

[ror3d]

This should solve #490

The problem was that the message box tries to split the description string after the first dot or colon, but if there is only a single dot at the very end of the string, when calling isspace(*it), the value of *it is \0 and crashes.

[CLAassistant]

All committers have signed the CLA.

[whitequark]

Thanks!

[ror3d]

Happy to help!

I've been using this for some days now and it's the simplest/most functional thing out there that does both 2D and 3D, and I really like that it doesn't try to do everything while having broken stuff everywhere. For its simplicity I think I can even contribute to it without spending weeks trying to understand the source, so expect some more PRs in the future, possibly :)

[whitequark]

For its simplicity I think I can even contribute to it without spending weeks trying to understand the source, so expect some more PRs in the future, possibly :)

A word of caution: it has a highly interdepenent implementation with a lot of hidden assumptions. Hack away, but note that anything you do that touches the core will probably have unintended consequences. I did my best to improve the situation but it's not much (yet).