Add consumes interface to METProducers

Since I got pointed at CSCHaloDataProducer I discovered RecoMET/METProducers had several other classes also missing 'consumes', although some classes already had been updated. No idea why only some were done. This branch formally adds the consumes interface where it was missing. But BEWARE! I am no expert on this code, and there is what I consider to be a rather complicated templated class MinMETProducerT that you probably normally wouldn't want me messing with, and now I've given it a vector<EDGetTokenT<METCollection> >. The whole package compiles and builds in 710pre4. But it is in no way tested. I wouldn't have a clue how to do that.