Drift correction updates

[enryH]

After adding the first basic functionality in #58 , there can still some improvements be done

• load files from GitHub
• define input format and which tool can produce it (maybe switch to metaboigniter output types)
• in the notebook some plotting function internally call the acore function, which needs to be separated: Show the acore code, use the output of a function in acore to plot.
• aradopsis seedling lipids data: to remove or to keep?