With this function, a specifically formatted xlsx file
can be loaded. After validation of the file,
'pmax' and other key values were examined for
the following analysis. The output is an ABT object.
An object of this class is a list with four contents named
DATA, pmax, longestFromSecond and
shortestFromSecond. DATA is a data.frame.
The other three are integer objects.
These values are used for the plotting functions
plotAllABT and plotEachABT.