* 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
Migrate tutorial text from individual `directions.txt` files to the main
tutorial document. Add some comments to source code to provide anchors
for inclusion.
