Refactor hasOrphans isFullyConnected

[Affie]

Clean/clear up connectivity functions, isFullyConnected and hasOrphans

For clearer understanding of exactly what the function does:
Deprecate:

• isFullyConnected
• hasOrphans

In favor of:

• isFragmented or similar

Add functionality:

• isFactorsFullyConnected

[Affie]

Since orphaned factors aren't currently allowed reserve isFactorsFullyConnected for future use.

A definition:

a graph G is connected if there is a path between each pair of vertices

• use name isConnected
  deprecate:
• hasOrphans - is misleading in the current implementation
• isFullyConnected - what does the fully imply, if we want to allow orphaned factors in the future does the fully mean all links that should be there is there?

[Affie]

We can also do isDisconnected = !isConnected