This PR corrects incoming backslashes to forward slashes on any paths passed in by the developer from a public API.

This is important because most Windows devs will use backslashes \ because that is what they are used to. This however is wrong for cross platform use. While we recommend people use forward slashes, people will either not notice or not care.

In particular the wildcard input of **\*.png won't work on any platform but **/*.png will.

These changes ensures things "just work" and reduces support requests.

Also fixed a spelling mistake.