#' @description Slice spectra contained in list-column of spectral tibble
#' (data frame). A list of x-axis value ranges can be specified. Spectra are
#' cut based on these ranges.
#' @param spc_tbl Spectral data in a tibble object (classes "tibble_df", "tbl"
#' and "data.frame"). The spectra tibble is expected to contain at least
#' the column \code{spc} (list-column with spectral matrices stored in a list)
#' and \code{wavenumbers} or \code{wavelengths} (list-column that contains list
#' of x-axis values).
#' @param xunit_lcol Character vector that specifies column name where x-axis
#' axis units are stored within \code{spc_tbl}. Default is \code{"wavenumber"}.
#' @param spc_lcol Character vector that specifies which column (list-column)
#' contains spectra to be sliced. Default is \code{"spc"}.
#' @param xvalues_cut List of numeric vectors that contains upper and lower bounds of respective regions to keep in spectra. The spectral regions outside
#' the \code{xvalues_cut} intervals will be cut out in the output spectra.
#' @return Spectral tibble (data frame with list-columns) with sliced x-axis
#' column and spectral column. Both the x-axis list-column and the spectral
#' tibble list-column only contain data specified within the \code{xvalues_cut}