Sodium (#1172)

* Use Native libsodium when available

* add newline

* fix typo of exports

* add to webpack ignore

* Update Secretbox.js

src/client/voice/util/Secretbox.js

@@ -0,0 +1,13 @@
+try {
+  const sodium = require('sodium');
+  module.exports = {
+    open: sodium.api.crypto_secretbox_open,
+    close: sodium.api.crypto_secretbox,
+  };
+} catch (err) {
+  const tweetnacl = require('tweetnacl');
+  module.exports = {
+    open: tweetnacl.secretbox.open,
+    close: tweetnacl.secretbox,
+  };
+}