API: deprecate from_csv in favor of read_csv

[jreback]

just too confusion and not consistent

related: #3418, #3171

Diffrent defaults for parse_dates is about all of it from looking at those two issues.
depreaction warning would be fine. removing completely is too harsh IMO
, due to breaking old code.

[jreback]

fair enough

[jreback]

closing in favor of #4916

[jorisvandenbossche]

Reopening this because #4916 is also more general about integrating functionality of the from_dict/records functions inside the DataFrame constructor.

Regarding deprecating from_csv, is this something we still want to do? Or has the ship sailed? (and we keep it as an alias with slightly different defaults indefinitely)