Renamed files for consistent filenaming, moved into email folder

A few things. Because all files are version controlled and git tracks
who did what, you don't need to add a "_DEN" to the end of the file.

I have also moved the email files into their own email folder, as that
makes more sense and compartmentalizes things.

And in terms of naming files, its good to be consistent within a
repository. Using websites and recommended guidelines, I developed
have created a filenaming convention/rules. I would like us to stick
to keeping files consistently named, for sanity and
organization. Thank you! :D

Filenaming Rules:

1) Keep the names short, but meaningful. Remove unnecessary words such
as the, and, a, etc.

2) Don't include spaces and avoid underscores. For a string of words,
capitalize the first letter of each word, except for the first word
(e.g. "fileNameDescription")

3) Use hyphens to separate important parts of the name or when there
is an abbreviation followed by another word (e.g.
"diabetesRisk-AnalysisOutput" which separates the two concepts, the
project descriptor ["diabetesRisk"] and the contents of the file
["AnalysisOutput"], or "report-AnalysisFoodIntake-2014.pdf" and not
"reportAnalysisFoodIntake2014.pdf").

4) Avoid redundancy in file names and file paths
(e.g. folderName/fileName-folderName.txt, instead use
folderName/fileName.txt, or
"diabetesSatFats/analysis-DiabetesSatFats.sas", use
"diabetesSatFats/analysis.sas")

5) If a number is included in the filename, such as for the version
number, use two digits not one (e.g. V01, not V1).

6) When including a date, include it at the very end of the filename
and in the international standard format YYYY-MM-DD.