Add newline for empty blocks {} (#205)

I find it weird to put `{}` together. So I figured I would change it to have an empty line and ask for feedback :)

![image](https://cloud.githubusercontent.com/assets/197597/21739279/062adc80-d44c-11e6-8bb7-5e0768f3ddde.png)

Beware: most of the test cases are not representative of real code, you almost never define blocks with no content in practice.

tests/node_tests/stream/__snapshots__/jsfmt.spec.js.snap

@@ -44,14 +44,18 @@ var data = \"foo\";
 
 ls.stdin.write(data);
 ls.stdin.write(data, \"utf-8\");
-ls.stdin.write(data, () => {});
-ls.stdin.write(data, \"utf-8\", () => {});
+ls.stdin.write(data, () => {
+});
+ls.stdin.write(data, \"utf-8\", () => {
+});
 
 ls.stdin.end();
 ls.stdin.end(data);
 ls.stdin.end(data, \"utf-8\");
-ls.stdin.end(data, () => {});
-ls.stdin.end(data, \"utf-8\", () => {});
+ls.stdin.end(data, () => {
+});
+ls.stdin.end(data, \"utf-8\", () => {
+});
 
 var ws = fs.createWriteStream(\"/dev/null\");
 ls.stdout.pipe(ws).end();