Removed .DS_Store, fixed #3, and made things consistently UTF-8

.DS_Store is not part of Snap!, so it shouldn't be in the repo. I also added a .gitignore so .DS_Store won't be added again with `git commit -a`, `git add -u`, `git add --all`, and friends.

I fixed trailing whitespace, whitespace on blank lines, non-unix newlines, and missing newlines at EOFin Snap!'s source files, as well as an encoding issue.

All files now use UTF-8.

Issue #3 is also fixed.