Update README.md

Add link for Wk 1 pres
Update README.md
add HSC data, modify slides a little
mods to presentation
Worked on Wk1 presentation
Update README.md
Add datasets, remove hsc data, cleanup the gitignore and unnecessary files
Add precip and nba data
Merge pull request #1 from allenaven/gh-pages

Updates to Wk 1 data, etc.