Move getMediaOutputForDimension into Media_Output_Component
Remove unneeded Events from image-enlarge
Remove double cache-delete for media-type
Add Image-group to every test related to images
Use only file-path for getResponsiveImageSteps instead of ImageData
Change responsiveWidthStep js-functions to private functions
Only reset src-attribute if screen becomes bigger.
Reset src-url in repeated call of onContentReady

To prevent loading of big images because of late execution of
ResponsiveEl.
Rename Kwc_Abstract_Test to ImageTest
Use different class to load assets
Remove unrelated line from test
Simplify code of isValidImage function
Move calculation into template-vars
Create separate tests for different situations
Use static width instead of generating width