Remove explicit default destructors (#157)

From CppCoreGuidelines:

Rule of Zero: C.20: If you can avoid defining default operations, do.
C.52: Use inheriting constructors to import constructors into a derived class that does not need further explicit initialization.
DRY forward and using declarations.
Miscellaneous:

Fix format.sh to output examples with normalised paths in sorted order.

Co-authored-by: ArthurSonzogni <sonzogniarthur@gmail.com>

include/ftxui/component/component_base.hpp

@@ -22,8 +22,7 @@ using Components = std::vector<Component>;
 /// @ingroup component
 class ComponentBase {
  public:
-  // Constructor/Destructor.
-  ComponentBase() = default;
+  // virtual Destructor.
   virtual ~ComponentBase();
 
   // Component hierarchy:
@@ -73,8 +72,6 @@ class ComponentBase {
   ComponentBase* parent_ = nullptr;
 };
 
-using Component = std::shared_ptr<ComponentBase>;
-
 }  // namespace ftxui
 
 #endif /* end of include guard: FTXUI_COMPONENT_BASE_HPP */