use deparse-substitute in the validation helper functions

[valentinitnelav]

For example in get_outliers.R, at .validate_tp instead of

stop(
      "\n
      'tp' is not a 'matrix', 'data.frame' or 'data.table'"
    )

use

stop( deparse(substitute(tp)), " is not a 'matrix', 'data.frame' or 'data.table'" )