switch to polka, remove unused deps

package.json

@@ -24,12 +24,12 @@
     "chokidar": "^1.7.0",
     "code-frame": "^5.0.0",
     "escape-html": "^1.0.3",
-    "express": "^4.16.2",
     "glob": "^7.1.2",
     "locate-character": "^2.0.5",
     "mkdirp": "^0.5.1",
     "mri": "^1.1.0",
     "node-fetch": "^1.7.3",
+    "polka": "^0.3.4",
     "port-authority": "^1.0.0",
     "pretty-ms": "^3.1.0",
     "relative": "^3.0.2",
@@ -50,7 +50,6 @@
     "@types/mkdirp": "^0.5.2",
     "@types/rimraf": "^2.0.2",
     "compression": "^1.7.1",
-    "css-loader": "^0.28.7",
     "electron": "^1.8.2",
     "eslint": "^4.13.1",
     "eslint-plugin-import": "^2.8.0",
@@ -63,7 +62,7 @@
     "rollup-plugin-json": "^2.3.0",
     "rollup-plugin-string": "^2.0.2",
     "rollup-plugin-typescript": "^0.8.1",
-    "style-loader": "^0.19.1",
+    "serve-static": "^1.13.2",
     "svelte": "^1.49.1",
     "svelte-loader": "^2.3.2",
     "ts-node": "^4.1.0",