Hats webpage: Many improvements and fixes (2nd try) * Fix static hats not being animated properly * Make widges more user-friendly * Add local mode to hats webpage to make testing easier (IS_LOCAL variable) * Cleanup code * Update themes list * Update list of local hats

Directory for automated tests to test the engine.

Run `ctest` in the root directory of this repository to run all tests.
Run `ctest -R <test name>` to run only the test with the given name.

This requires you to have CMake.