Added trailingNewline option

Adds or removes a newline from the end of the file.
Defaults to false (removal), as that's the current behavior.
Added commandline flag for trailingNewline
Added additional testcases for trailingNewline

Includes test for 'true when newline already present' and 'single line
input'
Merge pull request #8 from jkap/feature/trailing-newline-option

Added trailingNewline option