Multiple minor improvements over 2.3.0

2.3.3

• Changed deprecated _gather to pivot_longer (thanks to olivroy!)
• Fixed a bug where compare_df would mutate the global data to data.table

2.3.2

• Fixed an edge case with keep_unchanged_rows
• Removed naked stringsAsFactors from tests into data.frame creation function.

2.3.1

• prevented the compareDF function from mangling non-standard column names in input dataframes (thanks to lcougnaud!).