int ExistsProp (string name [, int sc])
mixed SetProp (string name, mixed arg [, int sc])
DESCRIPTION
Checks if this object has a certain property.
Arguments
name: the name of the property sought.
sc : if non-zero, only the 'soft property' is checked.
Result
0 if the property doesn't exist, non-0 else.
The function checks both for the existance of a lfun 'Query<name>'
or an entry in the property-mapping. If <sc> is non-zero, just the
mapping is checked.