Revert "update"

This reverts commit 72d1037ef2163a5dd2d1d229857da4ecb8eecbda.

	modified:   config.yml
	new file:   src/svg/arrow-bottom.svg
	new file:   src/svg/arrow-down.svg
	new file:   src/svg/arrow-top.svg
	new file:   src/svg/left.svg
	new file:   src/svg/right.svg
	new file:   src/svg/top.svg
	new file:   src/svg/ur.svg
optimized svg