Run stylelint on all SCSS files

This adds quotes so that globbing actually works as intended with `stylelint`.
Previously, we were relying on whatever a shell does with `**` style globs,
which meant that many files weren't picked up.

This means many files weren't being linted before, so the remaining commits will
fix those new errors.

package.json

@@ -49,7 +49,7 @@
     "lint": "eslint src/",
     "lintall": "eslint src/ test/",
     "lintwithexclusions": "eslint --max-warnings 0 --ignore-path .eslintignore.errorfiles src test",
-    "stylelint": "stylelint res/css/**/*.scss",
+    "stylelint": "stylelint 'res/css/**/*.scss'",
     "clean": "rimraf lib",
     "prepare": "yarn clean && yarn build && git rev-parse HEAD > git-revision.txt",
     "test": "karma start --single-run=true --browsers VectorChromeHeadless",