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/template/__snapshots__/jsfmt.spec.js.snap

@@ -14,7 +14,10 @@ var x = {
   \`
 };
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-var o = { [\`key\`]: () => {} };
+var o = {
+  [\`key\`]: () => {
+  }
+};
 
 var x = {
   y: () => Relay.QL\`