Other plotting functions:
plot_emission_intensity(),
plot_techmix(),
plot_trajectory(),
prep_emission_intensity(),
prep_techmix(),
prep_trajectory(),
qplot_techmix(),
qplot_trajectory(),
recode_metric_techmix(),
recode_metric_trajectory(),
scale_colour_r2dii(),
scale_colour_r2dii_sector(),
scale_colour_r2dii_tech(),
scale_fill_r2dii(),
scale_fill_r2dii_sector(),
scale_fill_r2dii_tech(),
spell_out_technology(),
theme_2dii(),
to_title()