Prefer logical punctuators instead of named operator keywords

Some compilers (eg. MSVC) still require inclusion of <ciso646>
in order to import named operator keywords.
It is easier to stick with traditional punctuators.

include/storage/io.hpp

@@ -96,7 +96,7 @@ class FileReader
     /* Read count objects of type T into pointer dest */
     template <typename T> void ReadInto(T *dest, const std::size_t count)
     {
-#if not defined __GNUC__ or __GNUC__ > 4
+#if !defined(__GNUC__) || (__GNUC__ > 4)
         static_assert(!std::is_pointer<T>::value, "saving pointer types is not allowed");
         static_assert(std::is_trivially_copyable<T>::value,
                       "bytewise reading requires trivially copyable type");
@@ -214,7 +214,7 @@ class FileWriter
     /* Write count objects of type T from pointer src to output stream */
     template <typename T> void WriteFrom(const T *src, const std::size_t count)
     {
-#if not defined __GNUC__ or __GNUC__ > 4
+#if !defined(__GNUC__) || (__GNUC__ > 4)
         static_assert(std::is_trivially_copyable<T>::value,
                       "bytewise writing requires trivially copyable type");
 #endif