code_review: PR #1416

- Split `DoubleTapped` into two methods: `CheckoutBranchByDecorator` and `CheckoutBranchByCommit`
- Move `DoubleTappedEvent` from whole ListBox to the row tapped actually
- Do nothing if the decorator double-clicked is HEAD
- Code-style

Signed-off-by: leo <longshuang@msn.cn>

src/Models/Watcher.cs

@@ -55,7 +55,7 @@ namespace SourceGit.Models
 
                 _watchers.Add(wc);
                 _watchers.Add(git);
-            }               
+            }
 
             _timer = new Timer(Tick, null, 100, 100);
         }