Redesigns, deletes and renames

Also noted authors propertly on contributed examples

Some examples included in this batch require the included libraries: `easings.h` and `raygui.h`. Examples included:

 - shapes_bouncing_ball
 - shapes_collision_area
 - shapes_following_eyes
 - shapes_draw_circle_sector (requires raygui.h)
 - shapes_draw_rectangle_rounded (requires raygui.h)
 - shapes_draw_ring (requires raygui.h)
 - shapes_easings_ball_anim (requires easings.h)
 - shapes_easings_box_anim (requires easings.h)
 - shapes_easings_rectangle_array (requires easings.h)