Honor Rule of three (or five) in the class wizard

It is very often a mistake to define a destructor without a copy (and move)
constructor and assignment operator. In C++11 no move constructor and
assignment operator will be generated if a destructor is defined. So it is
better to omit a lonely destructor in out template.

https://en.wikipedia.org/wiki/Rule_of_three_%28C%2B%2B_programming%29

Change-Id: If911556f872d878939f0f2fcaa974494a4df8a8a
Reviewed-by: Tobias Hunger <tobias.hunger@theqtcompany.com>