Allow --property flag to be omitted

[markrtuttle]

Currently, when the --property flag is omitted, the errors are reported as "other errors" without line numbers or traces. All that is missing is the property description from the --property flag. The output should be as usual for normal errors, just omitting the property description.

[markrtuttle]

The property-missing branch of the frok https://github.com/markrtuttle/aws-viewer-for-cbmc contains a preliminary implementation.