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/parser.cpp

@@ -11,9 +11,9 @@
 namespace YAML {
 class EventHandler;
 
-Parser::Parser() {}
+Parser::Parser() : m_pScanner{}, m_pDirectives{} {}
 
-Parser::Parser(std::istream& in) { Load(in); }
+Parser::Parser(std::istream& in) : Parser() { Load(in); }
 
 Parser::~Parser() {}
 
@@ -126,4 +126,4 @@ void Parser::PrintTokens(std::ostream& out) {
     m_pScanner->pop();
   }
 }
-}
+}  // namespace YAML