Require newline at EOF

Newline at EOF is is a common convention that most tools expect. Not
having a newline at EOF is considered the exception. Examples include:

- Vim explicitly says '[noeol]' (default is to add newline).
- Git explicitly says 'No newline at at end of file'.
- Bash `read` fails to read the last line of the file.

Most importantly, it would be nice to have the same convention in all
files instead of them switching back and forth.
Merge pull request #3 from jsageryd/johan

Require newline at EOF