* Ignore cmake intermediate build dir
* Fix C++ language version in cmake build scripts
* Set a default SDL2_ROOT_DIR value for macOS in cmake scripts
* Fixed macOS SDL framework linking in cmake scripts
* Added macos-cmake target for CI builds in github workflows
* Use C++17 for building Tests instead of 20, since we build them with VS2019 in some jobs
This adds the ability for geometry sets to store build settings that can
be automatically applied when they are loaded. This should allow sharing
of .gset files to demonstrate problems with certain settings on certain
files. It also allows people to diagnose problems more easily by being
able to dump their own triangle meshes and settings and load them in the
demo, with all of its visualization options. .gset files can be created
from the current mesh and settings by pressing the 9 key, which will
generate it in the same folder as the input mesh.
Also converts more of the demo to use STL.
* Tests live in a "Tests" folder alongside the other components. Inside the "Tests" folder, tests are split into folders by the component they test. For example, the example unit test of "rcVdot" (which is implmemented in Recast/Recast.h) lives in "Tests/Recast/Tests_Recast.h".
* Uses the Catch testing framework
* One example test of "rcVdot"
* Tests are run on Travis and Appveyor after every build. Failing unit tests will fail the build in both case.
* Added instructions on running unit tests to the readme
