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".

src/nodebuilder.cpp

@@ -11,7 +11,12 @@ namespace YAML {
 struct Mark;
 
 NodeBuilder::NodeBuilder()
-    : m_pMemory(new detail::memory_holder), m_pRoot(nullptr), m_mapDepth(0) {
+    : m_pMemory(new detail::memory_holder),
+      m_pRoot(nullptr),
+      m_stack{},
+      m_anchors{},
+      m_keys{},
+      m_mapDepth(0) {
   m_anchors.push_back(nullptr);  // since the anchors start at 1
 }
 
@@ -127,4 +132,4 @@ void NodeBuilder::RegisterAnchor(anchor_t anchor, detail::node& node) {
     m_anchors.push_back(&node);
   }
 }
-}
+}  // namespace YAML