Flatten column names and values with a comma-delimiter (#24)

[dm-p]

Applies to both Source and Destination node data roles.

e.g. if FirstName + LastName columns are supplied, this will name the field as `FirstName,LastName'

Values submitted to the request are then similarly flattened, e.g.:

["Daniel,Marsh-Patrick", "Desirree,Adegunle"]

This pattern will consolidate and delimit a smany columns as are supplied to each data role.

[lmeyerov]

@dess890 can you try building and confirming generates graph topology + edge src/dest/properities as expected?

[lmeyerov]

Great, merging!

@dm-p feel free to continue or delete branch