Add support for label combinations in a single string


Should add support for a single string that contains multiple labels, e.g. "Business&Voice", along with aliases for these in the PropertyLabels class. It's not obvious that people need multiple labels for common phone scenarios. It's good if I can get intellisense to help with this. This syntax also potentially opens up the ability to do "or" combinations of labels like "Personal|Business". Though probably not going to expose that immediately as part of this feature.