Streamline `workflows.Rmd`

[mdingemanse]

Streamline workflows.Rmd. Aims:

• Make maximally friendly to first time users
• Make code maximally elegant and succinct
• Present a small selection of visually appealing, self-explanatory plots

Tasks:

• Simplify code to transform data and generate plots
• Make plots visually appealing and self-explanatory
• Walk through a simple example of finding & filtering data to plot
• Add limitations section (here or elsewhere)

[mdingemanse]

Related: #111

[mdingemanse]

Example of an issue that needs fixing: quality_plot() output in vignette as rendered online doesn't look good, should be less high, the three plots should be square-shaped.