Fix the coloumn names (APC) and warning message

[Arvindiyer]

Yedong Pan (ydpan19@fudan.edu.cn) raised a query on the package via email as follows:

• APC as additional column. What does it represent?

• The warning message represented by the package, as mentioned below:
  [1] "-> Calculating APC threshold..." Warning message: In rbind(deparse.level, ...) : number of columns of result, 7, is not a multiple of vector length 6 of arg 2

• Adding the query over here so it can help other users if they have the same queries.

[Arvindiyer]

• APC and select_score are the same.

  • Internally, we had used APC as column name for select score. This will be fixed, in next iteration.

• Warning message should not have an effect. Will fix the same in next iteration.