Better Code for Background Colors

Updated instances of `background-color` and `background` to `bgcolor`
only.

https://litmus.com/blog/background-colors-html-email
Merge branch 'gh-pages'
Removed duplicate bgcolor

Removed duplicate bgcolor attribute from <body>
Matched MSO VML fill color

Matched MSO-specific VML fill color to match rest of template
Replaced curly quotes

Replaced curly single quotes with straight quotes (curly quotes throw
off some build processes)
Merge branch 'master' into gh-pages