this commit brings a new API called indicator-api.
The idea is to have a API where one entity (data_provider) can offer a
range and a value. The other entity (indicator.container) can then take
up these values and ranges and make them something to display on the
For now this is only implemented in spotlight. The range goes from 0 to
*num of elements*. the value is the currently active element. Floating
point numbers are used to indicate a animation between element A and B.
The same logic can be implemented for scrollers, where range goes from
0 to how often the viewport fits into the size of the content.
The overall idea of this implementation is to provide a easy to use
interface that can be used to pass double values from one widget to