Add .DS_Store and test/ to .npmignore

An oversight?

Previously:

npm notice === Tarball Contents ===
npm notice 1.2kB  package.json
npm notice 6.1kB  .DS_Store
npm notice 44B    .tesselignore
npm notice 5.1kB  readme.md
npm notice 26.0kB lib/index.js
npm notice 63.4kB test/index.js
npm notice 15.9kB test/tessel-mock.js

.npmignore

@@ -1,3 +1,4 @@
+.DS_Store
 .gitignore
 .jscsrc
 .nycrc
@@ -13,3 +14,4 @@ send.sh
 upgrade-firmware.sh
 upload-tar.sh
 watch.js
+test/