Support select/hide columns by running some conditions defined by LabTalk Script

Examples: x refers to column, j refers to column index

• x[10] = 2.5 //check if column’s 10th row is 2.5

• mean(x)> 2 //check if column’s mean is bigger than 2

• j==2 or j==7 //if it’s 2nd column or 7th column

Other minor improvements:

• Add Select Columns… menu under Column as well. It used to be under Edit: menu only— which was not obvious.

• Renamed the Test - Select if True button to Select button