Print zero-column data.frame properly#3363

Merged

mattdowle merged 3 commits intoRdatatable:masterfrom

heavywatal:print-zero-column

Feb 8, 2019

Commits on Feb 6, 2019

Print zero-column data.frame properly
heavywatal
committed

Commits on Feb 7, 2019

Tidied output; e.g. Null is specially for 0 row 0 col
mattdowle
committed

Commits on Feb 8, 2019

Fixed tests and added a new one to cover the fixed error
mattdowle
committed