* project-wide refactor to accomodate removal of "using namespace xyz"
to stop polluting top-level namespace with "std" as recommended by the
Google C++ style guide.
* use a pre-commit hook to enforce this
ref:
https://google.github.io/styleguide/cppguide.html#Namespaces
* that is, both in ci, pre-commit config and in the makefile
* makefile and ci args are a little more strict than the pre-commit ones
* use globs of the file extensions we're after
* add verbosity