bool Add(const char *label, const char *pattern)
This method addes one vector binding to an OEVectorBindings
instance. The ''label'' given as the first method argument is the
name that appears in the human readable version of a SMARTS, while the
''pattern'' given as the second method argument is the SMARTS that
should be used to replace the ''label''. If the pattern is parsed
correctly and the association is made in the OEVectorBindings
instance, the method will return boolean true. If the SMARTS pattern
is invalid or the association cannot be made the method will return
boolean false. All attempts to associate a SMARTS pattern with a
particular ''label'' after the first association succeeds will result
subsequent failures to create new assocations.