Env data clean - closes #12 & #20

[alvizek]

Erin - I created a new branch that adds the updated pull_environmental_data.R script from the env-data branch as well as the water_temp_regression.Rmd.

• Added the csvs and xlsx that were missing (e.g., battle_clear temp data)
• Added a site_lookup table and joined this with resulting datasets
• Fixed the weird predicted temp data and also noted the datapoints that were interpolated
• Fixed some site/stream name issues
• Added a current temp data source for the Feather HFC

I think this script is now is pretty good shape.

[ErinCain]

All your updates look good to me. But I was running into a problem with the package build. Was able to resolve on a different branch that I cleaned up with all your edits in it. I will merge that one and close this one.