fix: readFile returns UInt8Array instead of Buffer

BREAKING CHANGE: Reduces UMD build size from 34kb to 12kb so I think its worth it.

Author: billiegoose

src/__tests__/fs.spec.js

@@ -63,11 +63,11 @@ describe("fs module", () => {
     });
     it("read file", done => {
       fs.mkdir("/readFile", err => {
-        fs.writeFile("/readFile/readFile-buffer.txt", "HELLO", err => {
+        fs.writeFile("/readFile/readFile-uint8.txt", "HELLO", err => {
           expect(err).toBe(null);
-          fs.readFile("/readFile/readFile-buffer.txt", (err, data) => {
+          fs.readFile("/readFile/readFile-uint8.txt", (err, data) => {
             expect(err).toBe(null);
-            expect(data).toEqual(Buffer.from(HELLO));
+            expect(data).toEqual(HELLO);
             done();
           });
         });

src/index.js

@@ -105,8 +105,6 @@ module.exports = class FS {
             if (data) {
               if (encoding === "utf8") {
                 data = decode(data);
-              } else {
-                data = Buffer.from(data);
               }
             }
             cb(null, data);