v0.2.1

Published as a result of CRAN maintainers noticing two failing tests on one specific version of R (3.2.5 for Windows). While publishing that fix, I also addressed some small bugs in the package, described below.

Bug fixes

• tabyl() and crosstab() now appear in the package manual (#65)
• Fixed minor bug per CRAN request - tabyl() and crosstab() failed to retain ill-formatted variable names only when using R 3.2.5 for Windows (#76)
• add_totals_row() works on two-column data.frame (#69)
• use_first_valid_of() returns POSIXct-class result when given POSIXct inputs, and handles bad list inputs (specifically POSIXlt) (#71)