Remove all .DS files

[dauntlessnomad]

Removing all redundant files from the repository.

[shinenelson]

For some reference about .DS_Store files, see my review applicable to #34, #35 and #36.

[shinenelson]

One more pull request to clean up .DS_Store files - applicable to #42.

[nikhiljohn10]

Add a .gitignore file with all unnecessary thing like these in it.