Require C++11 and remove support and use of `std::auto_ptr`

[Flamefire]

As previously announced this drops support for C++ prior to C++11 which allows to get rid of a few dependencies and conditional code and compatibility macros.

Going forward this will also simplify the code easing development especially due to use of (unconditional) move semantics.

It also drops the use and support of std::auto_ptr avoiding deprecating warnings and pitfalls.

Closes #90

[codecov[bot]]

Codecov Report

Merging #111 (564a422) into develop (903724c) will increase coverage by 0.04%. The diff coverage is 77.56%.

Additional details and impacted files

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