CMakeLists.txt:
- Searching for GTest package for unit testing.
- Added the new directory "Include" to the include file search path.
- Added the new subprojects "Example" and "UnitTests".

Example/CMakeLists.txt:
- New cmake file that compiles our Qt example.
- ToyRenderer is linked as a library.

Src/CMakeLists.txt:
- The ToyRenderer is now built as a library.
- Only the Qt Core library is linked for datastructures like QList.

UnitTests/CMakeLists.txt:
- Builds the first unit test.
- Links ToyRenderer as a library.

UnitTests/testtoyrenderengine.cpp:
- ToyRenderEngine is inherited by XToyRenderEngine to expose protected methods for testing.
- Sets up a ToyRenderer as a fixture, i.e. a class that can be used by all tests.
- A first small projection of two test triangles is made. The test runs successfully.