Run clang-tidy 7.0 with `-checks='-*,modernize-use-using' -fix`
against TU-s of all tests.
Manually refactor numerous typedef-s
- where missed by modernize-use-using check, not uncommon
- in code snippets in comments
Outcome is that searching for lower-case whole word typedef
in sources of all the tests should return no matches.
Add missing typename in mpl::if_ condition result.
Restore BOOST_CXX14_CONSTEXPR in boost::algorithm::clamp function
- apparently, GCC 5.5.0 does not compile it with C++11 constexpr.
Still not adding subchroma_image.cpp to toolbox test target
input sources due to run-time failure.
Depends on #176
