This was an old "include all" header, that we no longer want to be
usable, to make the include differences in new versions explicit.
We will introduce new "include all" headers later, in the form of
`catch_all.hpp`, `catch_matchers_all.hpp` and so on...
- 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