Delete .DS_Store

This hidden file shouldn't be in the repo.

From Wikipedia:

.DS_Store (Desktop Services Store)[1] is a proprietary format hidden file created by Apple Inc.'s Mac OS X operating system to store custom attributes of a folder such as the position of icons or the choice of a background image.[2]
Merge pull request #7 from willmot/patch-1

Delete .DS_Store props @willmot