Switch to GFED raw data

[znichollscr]

For gridding we need the biomass burning sectoral breakdown (#27 (comment)). This is doable from ESGF data, but it's a pain (basically because of the way the data is provided). This issue is to remind us to pick up the GFED raw processing we already have and use that instead. The ESGF data processing can then just act as a cross check if we want.

[jkikstra]

OK; so we clean & update 0102, and do a check that it adds up to the totals of the data provider (in a similar way as is done in 0103)?

Then, we should write a 0199_combine_sources.py to combine CEDS and GFED.

[znicholls]

Then, we should write a 0199_combine_sources.py to combine CEDS and GFED.

Nice, see #34