Created by: LKay
Adds simple, lightweight spinners to Bootstrap 4 as it was mentioned on nice to have feature list (#17021).
Includes 4 types of spinners, supports bootstrap colors, sizes and different positioning.
Works out of the box for new browsers. To support IE9, small fallback plugin is included which inserts special element instead of using :before element and basic animation for rotating the element.
Some basic tests are also included.
Can be easily extended with new spinner variations if they are compatible with single element CSS spinner such as Single Element CSS Spinners or Loaders Kit