* Added core_input_keys example
* Added core_basic_window example
* Added core_input_mouse example
* Added core_input_mouse_wheel example
* Added Rectangle struct
* Added core_input_gestures example to utilize the Rectangle struct
* Removed unused imports
* Used the right draw function for the example
* PEP8 fixes
* Added core 2d camera examples
* Added core 2d camera examples