resquin 0.1.1

• Changed the way the mahalanobis distance is calculcated in resp_distributions(),
  if missing values are allowed. Now within respondent mean imputation is used.
  Before missing values were turned to a value of 0, which is wrong in almost any
  case and would have skewed the results of respondents with missing values.
  Mean imputation is not an ideal solution, but it allows the observed data
  to influence the value of the mahalanobis distance value under missing data.
  Because within respondent mean imputation is not ideal, a new section
  in the description is added to call for caution when interpreting the mahalanobis
  distance values produced by resp_distributions() if min_valid_responses is
  smaller than 1.
• Polished documentation (fixing typos etc.)
• Added vignette on flagging respondents with flag_resp().
• Added a disclaimer for handling of missing data in resp_nondifferentiation.
• Added documentation on s3 methods.
• Fixed bug in s3 print function which would crash if resp_styles() was used
  on even numbered response scales.
• Added tests for functions added since 0.0.2.
• Now depends on R version being >= to R version 4.1.
• Added example data set nep from the GESIS panel.