- Overrides added
- usages of push_back() replaced with emplace_back()
- Loop variable made const-refernce
- NULL replaced with nullptr
- Names used in the declaration and definition unified
- size() replaced with empty
- Identical cases merged
* Use Xenial as the base distribution
* Remove C++11 builds
* Add a lot more C++14 builds
* Add some C++17 builds
* Include newer versions of Clang and GCC