Added biomethane options from solid biomass for industrial processes. Changed the model starting year from 2015 to 2020. Added further climate targets (climate neutrality in 2045).

Added technology concepts for low emission small-scale fluidised bed combustion systems. Added further biomass product caegories for these systems.

Minor language and online readability changes

See merge request !1

Minor language edit

See merge request !2

Copyright addition

See merge request !3