Some classes have virtual functions but not virtual constructors, causing -Werror=non-virtual-dtor #105

We have -Wnon-virtual-dtor -Wall -Werror in our g++ command which compiles with mFast headers. We are getting below issues:

..../mfast/instructions/template_instruction.h:50:7: error: ‘class mfast::template_instruction_ex<template_shse::hkSnapshot_cref>’ has virtual functions and accessible non-virtual destructor [-Werror=non-virtual-dtor]

We need to find out all the classes with similar issues and add virtual destructors to them.