Generalized met workflow

met.workflow.gen.R can be used for 
- downloading raw NARR
- converting to raw NARR to CF 
- Rechunk/Permuting for faster extraction times
- extracting for specific sites
- met2model.SIPNET (ED2 should also be working)

parameters are set in met.workflow.params.R
Yes I was using that too. Honestly this is here because I'm not keeping track of all the db connections. It's easy enough to clean up so that killdbcons() won't be necessary.