Support for civil Package (Date, DateTime, civil.Time)

[pjebs]

It would be good if a Dataframe can support

• civil.Date (ie. 1955-04-30)
• civil.DateTime (this is not the same as time.Time)
• civil.Time
• time.Time (already mentioned in numerous other issues eg Add support for more types #22)

• Also the ability to sort
• Also on loading, specify a column needs to be interpreted using custom parse which produces a type mentioned above.

Ref: https://godoc.org/cloud.google.com/go/civil

[pjebs]

https://github.com/rocketlaunchr/dataframe-go library supports generic datatypes.

[kniren]

Time support is desired, but I would not want to add any dependencies to external packages. I'm closing this issue in favor of #93 and others.