* Updated output message
* Use 'target_compile_definitions' for HAVE_LOG and HAVE_EXP
Previously, the change from using TutorialConfig.h to
target_compile_definitions happened without explanation as part of Step 8.
* Fix typo in #include
* Remove CMakeLists file that users should create
* Clarify which files users are expected to create
* Highlight the importance of configuring TutorialConfig.h.in after
the MY_MATH option has been set
* Update minimum required version to 3.10
* Use VERSION argument to project command rather than separate variables
* Replace `endif(USE_MYMATH)` with more modern `endif()`
* Simplify the call to 'configure_file()'
* Add comments to tutorial.cxx to use as anchors in documentation
* Remove CMakeLists and TutorialConfig.h.in files that users should
create. Consequently, remove Step1 from CMake tests.
Migrate tutorial text from individual `directions.txt` files to the main
tutorial document. Add some comments to source code to provide anchors
for inclusion.
Create a `Help/guide/` directory to hold guide-level documents.
Build them in most documentation formats, but not as man pages.
Initialize the guide directory with a placeholder for the tutorial.
