create a method to target missing scans only

[pavel-shliaha]

When acquiring many conditions, some will not have enough replicate due to their scans lost due to inadequete injection times. It would be great to have a function that accepts:

1. an assembled topDownSet
2. XML for method creation (or parameters to create it)
3. then looks for conditions having less than 2 replicate scans and writing a new XML that contains conditions, that were supposed to be acquired, but got lost

as an example take myoglobin dataset, without the scans extracted from files called myo_missing_scans.raw

[sgibb]

Now we have ScanDescription it should be easy to create a method.xml for missing scans. Can you create an example dataset with the new ScanDescription parameter for me?