refactor performance output

[GliderGeek]

• complete performance should be available in a variable
• this variable is used as input for excel writer
• this performance variable should be returned when command-line version is run
• this can be tested for #101

[GliderGeek]

First and last bullet are covered in commit a854b04f3387b86ed0ac96eab87cc9a6a8f95d01. remaining will be put in separate issues