Data file collation is wrong

[JG-QuarkNet]

Data files, identified by labels like 5.1, 10.6, etc., do not collate properly because they are strings, but we want to order them like integers. For example, the following listing might show up in the "Choose your data file" column of the index page:

10.7
10.8
10.9
100.1
100.11
100.12
100.13
100.14
100.15
100.16
100.17
100.18
100.19
100.2
100.3
100.4
100.7
100.8
100.9
25.1
25.2
50.41
50.42
50.43
50.44
50.45

Representing the data file format as 'N.M', these should be collated first by 'N' and then sub-collated by 'M'. Both should be treated as integers, so '10' should come between '9' and '11', not between '1' and '2'.