Data updates

[chris-prener]

The follow data updates are planned:

• integrate data from the CDC's 2017 data release for stl_tbl_asthma, stl_tbl_insurance, and stl_tbl_smoking
• update the murder data for St. Louis through 2017, add x,y coordinates to practice projection - these should be latitude/longitude coordinates so that students can also use leaflet with these data
• add a companion to stl_tbl_murders - either robberies or aggravated assaults? add x,y coordinates to practice projection - these should be latitude/longitude coordinates so that students can also use leaflet with these data
• update stl_tbl_income to add 2016 data as well
• add stl_tbl_race for 2016
• add stl_tbl_pop for 2016
• add stl_tbl_race with additional years of data for more practice with tidyr
• add more point locations to stl_tbl_sluPlaces