- Bugfix: Biggest version of heatmap of comparisons of custom gene lists showed wrong clustering.

- Bugfix: The zscore() function of the R "liver" package changed standard behavior with the update to version
  1.19. I created a clean custom function for z-score calculation. It now behaves like the built-in scale()
  function in R, but is able to ignore NA values, and now makes the script independent from the liver package,
  which is no longer required.

- Improvement: The color palettes of PCA scores plots have been changed to colors that are distinguishable
  by many colorblind people. The color palettes used are "paletteMartin" from the package "colorBlindness",
  and a selection of colors from the palette "Safe" from the "rcartocolor" package.

- Improvement: The color palettes of clusters in heatmaps have been changed to colors that are distinguishable
  by many colorblind people. The color palettes used are "paletteMartin" from the package  "colorBlindness",
  and a selection of colors from the palette "Safe" from the "rcartocolor" package.

- Improvement: The color ramps in heatmaps have been changed to colors that are distinguishable
  by many colorblind people. The color palettes used are "paletteMartin" from the package "colorBlindness",
  and a selection of colors from the palette "Safe" from the "rcartocolor" package.

- Improvement: The option to change the colors of PCA scores plots has been added to the R configuration file
  "configuration_r_analysis.R".

- Improvement: The option to change the colors of clusters in heatmaps has been added to the R configuration
  file "configuration_r_analysis.R".

- Improvement: The option to change the color ramps in heatmaps has been added to the R configuration file
  "configuration_r_analysis.R".

- Improvement: The color palette of the 3-d scatterplot of the gene PCA loadings has been changed to be
  distinguishable by many colorblind people.

- Improvement: Restrict the packages to install by the helper script to the absolute minimum. Only required
  packages will be installed, some of which will install/import other packages/dependencies.