met uncertainty tool (in PAT) fixes for 72X releases

The MET uncertainty tool in PAT has been updated accordingly to the last development changes in 72X releases, and can go to the central release now.

Pat MET names have been also updated in order to match the new naming convention.

Matthieu

@TaiSakuma 

So, for memory cost, assuming ~5 MET types in one AOD or RECO file,  as the corrections are not applied per default, with 10000 events which is the average of a file, I get 10000*8*5/1024/1024 = 0.22 Mb. I would not say this is the problematic point here, so I would keep it anyway.

Now for the type of the structure. It seems according to Chris that this CommonMETData structure is not following the CMS rules, so we need anyway to rewrite it and adapt the met classes using it. 
In addition to that, the question of the definition of phi stay the same, we don't know what people would do with met_x and met_y during their development. So giving them a locked framework would be much simpler.

What do you think?