Sort the generated classes by name

[PatrickRose]

The classes that are generated are done using symfony's finder class, which can return files in any order returned by the filesystem.

This means that running the typescript:generate command can generate incredibly noisy diffs - whereas at least if it's sorted then the diffs should be slightly more sensible.

[bobbypiper]

@lepikhinb any chance of getting this merged? @PatrickRose has solved an ongoing problem for our team - this minor PR mitigates noisy diffs for our services.