Update General Code Style

[lindseywild]

This came out of an HTML & CSS Task Force meeting.

Update or add general code style info:

• Tabs, no trailing white space, empty lines at the bottom of files, how linters are setup
• How we write comments
• Provide examples in our existing projects of good implementation of the standards
• Reorganize things if necessary
• Anything else!

[mdt2]

• Tabs (already covered in the "use two spaces" piece)
• No trailing white space (already covered)
• Empty lines at the bottom of files (already covered)
• How linters are setup (linters are already mentioned in the build_process readme with links to documentation on setting them up)
• How we write comments (added some additional details about this)

This ended up being a much smaller PR than I expected: #197