Structure for an energy price plot.

Introducing a basic series of colour palettes for consistent plot styling
Rename grey scale to styles
Defining interaction style for plotting
Added a mixed energy plot... Need to test it using the data sets at home
Added axes labelling
Docstrings, altered functions to optionally take a compiled price series to cut
down on duplicated effort
Added Makefile
Regenerating docs
Added alt greyscale plot styles
deleting doc files
Couple lambda functions to increase readability
Boiler plate around reserve histogram
Changes to boiler plate
Minor linting
Merge branch 'feature/vSPD_plots' into develop