Improve default namespace skips.
Improve default namespace skips.

- Check every parsed namespace instead of running a global regex on the
whole input
- Check for namespaces ending in tns.xsd and allow schemas hosted on
different URL's than the default one.

NativeScript/NativeScript,NativeScript/NativeScript,NativeScript/NativeScript,NativeScript/NativeScript,NativeScript/NativeScript