Insert the ExcelOutput object that outputs the results from the calculation of statistical measures and distribution fitting statistical test in a given data sample

Insert two scripts, ImportExceldata to import data from Excel files and ReplaceMissingValues to replace the missing values in a data sample

It's probably better to have a new description field for this

but list all the properties instead

TODO: the GUI will have to make it a float too

Notes:
  * Input format changed (Source.part now is a full name)
  * __init__ must handle complex data structures for processingTime & interarrivalTime instead of having flat parameters
  * type conversion must be performed ("1" != 1), probably we can assume json has correct type and have the gui produce proper json