First step in re-organization: Topic outline
Dividing topics into Days
Cleaning up
Added directories for notes, etc.
Routine commit after small starts to course notes.
NCI from Mengdie

Small edits to narratives
Stream Metabolism case study added.
zip code scraping
Initial commit of geom-arrow, based on geom-field from  https://github.com/hadley/ggplot2/wiki/Creating-a-new-geom
geom arrow actually runs, though it doesn't do much useful...
much more funcitonal, refactored to just use segmentsGrob directly, still need arrow
eliminated amateurish debug code
geom_field: arrows work, but no alpha channel
rename geom_field to geom_arrow & comment
renamed narrative writeups for clarity
fixed figures in Wind Vector writeup
Add speed and angle to glyph-ready wind vector dataset
fix serious bug in geom-arrow (missing comma) and tweak arrow size
arrow size; fix bug in functions.R
rerun fetch with fixed functions.R