The old library had this class/module style. Now that we have CommonJS we could probably move to other concepts.
For singletons I think module scoped variables and functions like in the src/openpgp.js are a way to go.
For classes I would like to use the style as in Key and Message class. For the whole packet layer in src/packets and
the types in src/type it would make sense to port this to the class style. It's more efficient in terms of memory consumption
and also looks better in the debugger if you have a separation of attributes and methods.