Fixing ImportError in vmw.ZSI.twisted.WSresource.py while importing NoRe...

"NoResource" was removed from <code>twisted.web.resource</code> since **Twisted 12.2**, so using the one in <code>twisted.web.error</code>.

Further on, could you possibly update **PyPI** package in order to fix another ImportError while importing the <code>vmw.ZSI</code> module, due the unexistant <code>\__init\__.py</code> file in "vmw.zsi/vmw" folder ?

Thanks for the great contribution !