Apply formatting/style tweaks to comply with compile time diagnostics for g++ and clang++ (#686)

* Add compilation flags: -Wshadow -Weffc++ -pedantic -pedantic-errors
* Delete implicit copy & move constructors & assignment operators
  in classes with pointer data members.
* An exception to the above: Add default copy & move constructors &
  assignment operators for the Binary class.
* Convert boolean RegEx operators to binary operators.
* Initialize all members in all classes in ctors.
* Let default ctor delegate to the converting ctor in
  Binary and RegEx
* Don't change any tests except regex_test (as a result of the change
  to binary operators).

Note: https://bugzilla.redhat.com/show_bug.cgi?id=1544675 makes
-Weffc++ report a false positive in "include/yaml-cpp/node/impl.h".

include/yaml-cpp/contrib/anchordict.h

@@ -22,6 +22,7 @@ namespace YAML {
 template <class T>
 class AnchorDict {
  public:
+  AnchorDict() : m_data{} {}
   void Register(anchor_t anchor, T value) {
     if (anchor > m_data.size()) {
       m_data.resize(anchor);
@@ -34,6 +35,6 @@ class AnchorDict {
  private:
   std::vector<T> m_data;
 };
-}
+}  // namespace YAML
 
 #endif  // ANCHORDICT_H_62B23520_7C8E_11DE_8A39_0800200C9A66