Fix for xslt deprecation.

[HansBusch]

Add js based wsdl viewer.

[willysagefalk]

For event.wsdl, the likely root cause is that it imports external WS-* resources over http://, for example OASIS and W3C WSDL/XSD files. The current viewer/XSL appears to dereference imported WSDL/XSD files using document(...), which means the browser-side SaxonJS transform tries to fetch these external HTTP resources. Since the preview page is served over HTTPS, this is likely blocked by mixed-content/CORS restrictions. The transform then fails and the viewer shows a blank page instead of an error.

Suggested fixes:

The browser-side WSDL viewer should not dereference remote absolute http:// or https:// imports directly. It should either skip them in preview mode, use local mirrored copies, or go through a same-origin proxy.
wsdl-viewer.html should catch SaxonJS transform errors and show a visible error message instead of leaving the page blank.
Standalone XSD files such as humanbody.xsd and humanface.xsd should probably not be routed through the WSDL viewer unless we also add a proper XSD viewer.
Minor cleanup: several generated links contain ../..//; these should be normalized to ../../.

Expected behavior: the viewer should render the local WSDL content even when external imports are skipped, and show a warning/error message instead of a blank white page.