Separate Library Calls

Separate library calls as ggplot2 did not load properly.
Create plot5TotalByYearMV.r Function

Create plot5TotalByYearMV.r function to plot total PM2.5 emissions by
year for coal then save as PNG using ggplot2 package. Can create
multiple plots by FIPS (location).
Create plot6TotalByYearMVBaltLA.r Function

Create plot6TotalByYearMVBaltLA.r function… which is just a copy of
plot5TotalByYearMV.r with default FIPS for Baltimore, MD and Los
Angeles County. Assignment required a separate function for each plot.