Rework Legacy PNG Icons with Font Awesome SVG

Existing implementation handle icon with PNG, with manual positioning
with CSS background image.

This PR rework icons with Font Awesome SVG:

  - Locally venor Font Awesome v5.15.4 `expand-solid.svg` and
    `compress-solid.svg`
  - Rework styling with SCSS
  - Fix accessibility (see Leaflet#110)
  - Test with Leaflet v1.7.1
  - Update demo with above changes

Fix Leaflet#98
Fix Leaflet#102
Fix Leaflet#103
Fix Leaflet#110
Fix Leaflet#114

Signed-off-by: Wong Hoi Sing Edison <[email protected]>

Author: hswong3i

.gitignore

@@ -1 +1,2 @@
 node_modules
+package-lock.json

Makefile

@@ -1,14 +1,16 @@
 # See the README for installation instructions.
 UGLIFY = node_modules/.bin/uglifyjs
+SASS = node_modules/.bin/sass
 
-all: \
-	$(shell npm install) \
-	dist/Leaflet.fullscreen.min.js \
+.PHONY: all
+all: dist/Leaflet.fullscreen.min.js dist/Leaflet.fullscreen.min.css
 
+.PHONY: clean
 clean:
-	rm -f dist/Leaflet.fullscreen.min.js
+	rm -f dist/Leaflet.fullscreen.min.js dist/Leaflet.fullscreen.min.css
 
-dist/Leaflet.fullscreen.min.js: dist/Leaflet.fullscreen.js
-	$(UGLIFY) dist/Leaflet.fullscreen.js > dist/Leaflet.fullscreen.min.js
+dist/Leaflet.fullscreen.min.js:
+	$(UGLIFY) src/Leaflet.fullscreen.js > dist/Leaflet.fullscreen.min.js
 
-.PHONY: clean
+dist/Leaflet.fullscreen.min.css:
+	$(SASS) src/Leaflet.fullscreen.scss dist/Leaflet.fullscreen.min.css