Change MET term calculation order

As MET value is actually dependent on the order, I changed the order to be "the usual one". This is what I got from @khoo:

The exact ordering that you choose might depend on the analysis and object selection, e.g. H->gammagamma might choose photons with higher purity than electrons, and wish to prefer these. But assuming typical PID working points, one would probably want to do:

1. Electrons (most pure)
2. Photons (quite pure)
3. Taus (less pure)
4. Muons (only track-based OR, typically don’t remove anything else nor removed by anything else) Because electrons, photons and taus ~always generate jets, putting jets ahead of anything else will just veto the rest, hence the prescription to do jets last. The soft terms are just defined by whatever is not in another term, so of course are also affected by any OR decisions.