Begin replacing YAML with python objects
Merge remote-tracking branch 'origin/master' into develop
Change treaty year ranges from 100 to 500% and make optional
Change treaty year ranges from 100 to 0% (reversed) and make optional
Change treaty year ranges from 100 to 0% (reversed) and make optional
Add default equation set, and improve equation loader
Cleanup logging
Fix jacked up 2005 emissions variable
Change abatement form % to $ amount
Change damage and output functions
 to match documentation rather than Nordhaus
 (math is the same).
Add backstop
Change equations to match GAMS
Change equations to match new PDF docs
Begin zoomable graphs
Improve units in YAML config
Fix division by zero
Replace linspace with empty/fill
Add basic optimization
Fix exponent multiplier in rr
Replace linspace with arange