suggestion: set the read_spss() argument verbose from T to F

[frankcsliu]

In a knitted Rmd file, the progress bar will be printed into the output file as the argument was set to T by default. I think this is not necessary to turn it on by default as it will make the document too long with the progressing messages.

Please also consider to apply this verbose=F to sjPlot::view_df(). Thank you.