fix to dbfile.input.insert

fix wrong input select statement. it requires both start and end date
to do proper select.
add rhdf5 to dependences for met2model.ED
fix download ameriflux code

- now does not assume V003, but any version will do
- added list of mapping from site_id to ameriflux site names
- name files already to right name prefix.year.nc
- write all files independently to bety database
leverage of correct names in download.ameriflux
small fixes
make sure to only install rhdf5 if needed.
functions to execute remotely

- remote cmd execute, returns stdout
- remote R execute returns last variable
- remote copy, copy files
no longer write results to database

returns a data frame that can be used to write the files into the
database. This allows the function to be executed remotely (using
remote.execute.R).

Function now takes a siteabbev as input instead of site_id.
missing functions
return results that can be used to insert into bety
Merge branch 'master' into fix-met-workflow
return results add start/end year
use site as prefix
big clean up

- add start/end year
- remove TA and PAR and PREC
clean up gapfill
allow editing of pecan.xml #244
Merge pull request #269 from PecanProject/fix-met-workflow

Fix met workflow