Update to rustfmt-preview (#348)

* Update to rustfmt-preview.

* Run "cargo fmt --all" with rustfmt 0.4.1.

rustfmt 0.4.1 is the latest release of rustfmt-preview available on the
stable channel.

* Fix a long line that rustfmt 0.4.1 can't handle.

* Remove unneeded commas left behind by rustfmt.

lib/entity/src/packed_option.rs

@@ -33,7 +33,11 @@ impl<T: ReservedValue> PackedOption<T> {
 
     /// Expand the packed option into a normal `Option`.
     pub fn expand(self) -> Option<T> {
-        if self.is_none() { None } else { Some(self.0) }
+        if self.is_none() {
+            None
+        } else {
+            Some(self.0)
+        }
     }
 
     /// Maps a `PackedOption<T>` to `Option<U>` by applying a function to a contained value.