* cleanup cmake files to be a little more moderen
keep the source tree free of build artifacts
cmakelint the cmake files too
* fix cmake setup errors on CI
fix APPLE clang builds too
* CI needs support for realy history cmake V3.6
fix typo in cmake files using add_test() commnds
* One step more to use modern cmake
Prevent to modifiy compile and linker FLAGS and to set global includes
pathes
* fix CI build problems with older cmake versions
prepare cleanup cmake list file
* final cleanup
use Config.cmake.in and install hole cmake config files
* Fix cpp17 PORTABILITY_TEST linker problem
add missed target_link_libraries()
* hopefully prevent windows test problems
Progress towards #448
Lots of warnings from g++7.2, these are addressed in #423 which hasn't been merged yet.
CMAKE can be cleaned up a bit - may put back in the ability to use older cmake and just throw errors as necessary,
otherwise just force people to use at least cmake 3.1
