This function has been designed based on mzXML files obtained from
.d files (Agilent) using msConvert tool, in which we can find the collision
energy information. In addition to separate files by collision energies, this
function also changes the MS level of the high energy scans from 2 to 1
allowing their treatment (peak-picking for each collision energy, alignment,
i.e) with common software (xcms, mzMine2, enviPick, etc).