Incorporate the ChemInformatics data into the build process

[gwallison]

• [x] in build_nb, add the necessary instructions and infrastructure to capture the ChemInformatics info for as many chemicals as possible. This should include Hazards (.xlsx and .sdf) and the safety data (.xlsx)
• [x] At the minimum, put the presence/absence of the CI analysis into the bgCAS table so that downstream functions can access it.
• [x] A more thorough treatment would be to create a third table, indexed by bgCAS but with all the info scraped from CI

[gwallison]

Added field chemInfo_available into the data set that indicates if a bgCAS has ChemIformatics data available. A table with all the scores and authorities for those bgCAS is now in the repo's curation_files directory. In addition, the ChemInfo_ref_files dir in the final repo has the three results files from the CI request performed during the build. Those files are

• Hazard xlsx version - has the colored table as well as much of the data that was used to score the chemical
• Hazard sdf version - a text file that is used to create the simple score/authority table for the 20 characteristics
• Safety xlsx version - has a lot of summary information for each chemical and links to specific safety documentation.