Check UTF-8 encoding, and convert strings to UTF-8

Handle conversion errors properly by inserting � instead.  Add a binary
header to provide portable way to write binary literals (I like them) Also
add a test file.  ref #2404

src/utils/binary.hpp

@@ -0,0 +1,16 @@
+#ifndef BINARY_INCLUDED
+# define BINARY_INCLUDED
+
+template<char FIRST, char... REST> struct binary
+{
+  static_assert(FIRST == '0' || FIRST == '1', "invalid binary digit" );
+  enum { value = ((FIRST - '0') << sizeof...(REST)) + binary<REST...>::value };
+};
+
+template<> struct binary<'0'> { enum { value = 0 }; };
+template<> struct binary<'1'> { enum { value = 1 }; };
+
+template<char... LITERAL> inline
+constexpr unsigned int operator "" _b() { return binary<LITERAL...>::value; }
+
+#endif // BINARY_INCLUDED