Each plot has now its own function. This makes it easier to adjust the
creation and tweaking of a single plot. sma_plot_file() will now call
the individual plot function before saveing the plot.
This function loads the data and adjust some wrong column types. It
shoulb be used from all other scripts to load the data. It the same
source data for all following calculations.
The data is stored inside a 'tibble' from the 'tidyverse' package.
sma_plot_file(fname, ftype, title_list, legend_list, fun, ...)
can be used to write plot to a file.
It supports all output filetypes R can handle. Title and legend
arguments can be passed as lists.
All available plotting functions can be used, arguments go into a
variable argument list.
