chore(Settings): Define whitespace policy through EditorConfig

The project does not currently define a whitespace policy and
therefore had to reject a pull request. Instead of defining the
policy in a contribution section, we can benefit from the
EditorConfig project and the various IDE integrations
by defining a .editconfig file.
Merge pull request #40 from bripkens/master

chore(Settings): Define whitespace policy through EditorConfig