Issue #2298039 by lauriii, LewisNyman: Remove all PNG fallbacks for SVG.

core/assets/vendor/modernizr/modernizr.js

core/assets/vendor/modernizr/modernizr.min.js

core/misc/icons/000000/barchart.png

core/misc/icons/000000/file.png

core/misc/icons/000000/move.png

core/misc/icons/000000/orgchart.png

core/misc/icons/000000/paintbrush.png

core/misc/icons/000000/people.png

core/misc/icons/000000/puzzlepiece.png

core/misc/icons/000000/questionmark-disc.png

core/misc/icons/000000/wrench.png

core/misc/icons/0074bd/chevron-left.png

core/misc/icons/0074bd/chevron-right.png

core/misc/icons/424242/loupe.png

core/misc/icons/505050/loupe.png

core/misc/icons/5181c6/chevron-disc-down.png

core/misc/icons/5181c6/chevron-disc-up.png

core/misc/icons/5181c6/twistie-down.png

core/misc/icons/5181c6/twistie-up.png

core/misc/icons/73b355/check.png