Data logging functionality

[chozillla]

Issues with appending the data to the excel file. Writematrix does not work with appending and specifying the value and the slider. Maybe try the tag?

[chozillla]

Make the variable that logs and the stop and start as a global variable. Create the changes in a matrix or variable. Save the file as delimited text file or tabulated text when the user hits stop. Remove line 190-192 since gaintable_og is already set.