Add EPA2015_MONMEAN emissions as option and retire NEI2011

Barron Henderson, Lyssa Freese, and Patrick Campbell provided updated
EPA NEI 2016 emissions for incorporation into GEOS-Chem. These are to
replace the NEI 2011 emissions currently in HEMCO_Config.rc. This inventory
(denoted EPA2016_MONMEAN) is off by default in favor of the CEDS v2 global
anthropogenic emissions which extend to 2019.

For this inventory, the text from the EPA_Config.rc file provided by Barron
has been copied into HEMCO_Config.rc. Fixes made to that text include:
(1) adding entries for SOAP and pFe and (2) removing unnecessary
scale factors 256 and 256 for BCPO and OCPO.

NOTE: Currently mask 1007 (CONUS_MASK) is used for the EPA2016 entries, but
there are fields named for "can" and "mex" containing emissions over Canada
and Mexico. We may need to modify the mask to include those emissions.

For more details, see feature request #547

Signed-off-by: Melissa Sulprizio <mpayer@seas.harvard.edu>