* cmake: cpptoml allow usage of installed dependency

* CMakeLists.txt fix

* fixes build errors

* cmake: Added option "SPDLOG_SETUP_CPPTOML_EXTERNAL" to allow cpptoml library as installed dependency.

* build fix

* cmake: cleanup

* cmake: wrong option in "configure_file"

* unit_test.cpp fix

* cmake: travis and appveyor tests extended

* travis.yml : tabs removed

* fix travis test

* cmake: clear tab and newline characters.

* Additional description

* cmake: move cpptoml_config.h.in to cmake folder
cmake: add option SPDLOG_SETUP_INCLUDE_UNIT_TESTS
travis: build script adjusted

* fix travis

* travis: revert changes

* clang-format fix