Incorporate use off PPP package

[kbmorales]

Addresses the following issues:

42

43

21

19

Created an R package using code in this repo by @JohnMcCambridge and myself to download PPP data and make one clean unified PPP data set for analysis (for R users).

The package also incorporates an improved NAICS matching that iterates through subsequently older versions of NAICS index files from the US Census website.

This PR makes a script inbin/setup.R that will install the package and run the main assembly function in that package.

[kbmorales]

Hey John just pushed changes to the ppp package that should resolve the wd issue. Can you test it out again and let me know if that works?

[JohnMcCambridge]

retested, seems to be working well, perhaps some edge case issues we can continue to look at, but attempts at replication have failed.