Remove intermediary variables for message construction

[grahamalama]

My goal with this PR was to remove as much intermediary munging / formatting as possible to get from DataFrame -> printed message.

The flow was, in general:

• Read CSV
• create variables to hold calculated values
• create variables to hold strings with calculated values interpolated
• concatenate all of the variables containing formatting strings
• print message

Now, the flow is:

• Read CSV
• create (fewer, or at least that's the goal) variables to hold calculated values
• interpolate variables directly into message template
• print message