dw_list_charts using function that is deprecated with later versions of R

[epowell42]

When I run dw_list_charts, I get the message that default.stringAsFactors() is defunct and users should use stringAsFactors = FALSE. This appears to be triggered by the line out <- bindrows(parsed$list) in the dw_list_charts() function.

[munichrocker]

Is this a possible duplicate of #74 ?