Support insert_final_newline

[chapmandu]

Correct me if I'm wrong but cfformat seems to always create a final newline at the end of files.

This can become a problem when trying to prevent whitespace.

It would be great to have some sort of "insert_final_newline": true/false setting.

[jcberquist]

The newline at the end of the file is a result of the way blocks and opening to closing tags (e.g. <cfcomponent></cfcomponent> are formatted. I could update the formatter to trim what it gets back before writing to the file, but I will need to think about whether I want to allow files that don't end with newlines. I personally don't like files that don't end in newlines, since I think of it as the line terminator. Github in fact renders such files with a little red icon indicating the missing newline (as I am sure you know).