perf: 60ms improvement: Replace fs-extra with mkdirp/rimraf/cp-file

In Electron apps, the cost of large modules is very real.

fs-extra is very convenient, but removing it caused 50 fewer unique
files to be required(), resultin in 60ms faster startup!

Before: 557 unique requires (1330-1340ms)
After: 507 unique requires (1270-1280ms)

package.json

@@ -18,6 +18,7 @@
     "bitfield": "^1.0.2",
     "capture-frame": "^1.0.0",
     "chromecasts": "^1.8.0",
+    "cp-file": "^3.2.0",
     "create-torrent": "^3.24.5",
     "debounce": "^1.0.0",
     "deep-equal": "^1.0.1",
@@ -25,11 +26,11 @@
     "drag-drop": "^2.12.1",
     "electron": "1.4.2",
     "es6-error": "^3.0.1",
-    "fs-extra": "^0.30.0",
     "iso-639-1": "^1.2.1",
     "languagedetect": "^1.1.1",
     "location-history": "^1.0.0",
     "material-ui": "^0.15.4",
+    "mkdirp": "^0.5.1",
     "musicmetadata": "^2.0.2",
     "network-address": "^1.1.0",
     "parse-torrent": "^5.7.3",
@@ -37,6 +38,7 @@
     "react": "^15.2.1",
     "react-dom": "^15.2.1",
     "react-tap-event-plugin": "^1.0.0",
+    "rimraf": "^2.5.2",
     "run-parallel": "^1.1.6",
     "semver": "^5.1.0",
     "simple-concat": "^1.0.0",
@@ -56,13 +58,11 @@
     "electron-winstaller": "^2.3.0",
     "gh-release": "^2.0.3",
     "minimist": "^1.2.0",
-    "mkdirp": "^0.5.1",
     "nobin-debian-installer": "^0.0.10",
     "nodemon": "^1.10.2",
     "open": "0.0.5",
     "plist": "^2.0.1",
     "pngjs": "^3.0.0",
-    "rimraf": "^2.5.2",
     "run-series": "^1.1.4",
     "spectron": "^3.3.0",
     "standard": "*",