added attempt at showing constrol structure for markings (the xpath to which the markings apply)
removed display of marking's control structure (xpath)
display a warning that marking data is not fully supported in stix-to-html yet
added template that produces warning message when MAEC content is encountered

This means any content that matches the following xpath:

```xpath
*[fn:resolve-QName(fn:data(@xsi:type), .)=fn:QName('http://stix.mitre.org/extensions/Malware#MAEC4.0-1', 'MAEC4.0InstanceType')]
```