Add reason for new lines at end of files

[ESWAT]

Fixes #93. Links to this article to explain why it should be done, specifically for JS files.

[zatkin]

This has to do with a system distinguishing between text files (containing "lines") and binary files (which typically don't contain "lines").

More here: http://markmail.org/message/5jsn4epq7ad3vyvt

[zackdouglas]

This is my reasoning:
https://gist.github.com/zackdouglas/0d4ce1a755e683332c64/revisions

If a newline is added, it is immediately clear that no existing logic is changed simply by adding logic.