added Type Jam puzzle app for review (#1554)

* added Type Jam puzzle app for review

* pr round 2 prep

* updated ci scripts for varfont_shader_puzzle

* resolved unused and minor variable naming issues

* rotator tiles row and col are final vars now

* removed unused import and print from production

* made constructors const where needed

* pages_flow export refactored to directly come from that file

* removed old api commented out section from FragmentShaded

* updated pubspec yaml to correct project name

* dart min version updated; removed unnecessary commented out dependencies from pubspec.yaml

* updated pubspec.yaml min flutter version to ensure FragmentShader support

* added/edited comments for explanation, esp on var fonts; removed obsolete comments

* trailing newline added to pubspec.yaml eof

experimental/varfont_shader_puzzle/ios/Runner/Assets.xcassets/LaunchImage.imageset/Contents.json

@@ -0,0 +1,23 @@
+{
+  "images" : [
+    {
+      "idiom" : "universal",
+      "filename" : "LaunchImage.png",
+      "scale" : "1x"
+    },
+    {
+      "idiom" : "universal",
+      "filename" : "LaunchImage@2x.png",
+      "scale" : "2x"
+    },
+    {
+      "idiom" : "universal",
+      "filename" : "LaunchImage@3x.png",
+      "scale" : "3x"
+    }
+  ],
+  "info" : {
+    "version" : 1,
+    "author" : "xcode"
+  }
+}

experimental/varfont_shader_puzzle/ios/Runner/Assets.xcassets/LaunchImage.imageset/README.md

@@ -0,0 +1,5 @@
+# Launch Screen Assets
+
+You can customize the launch screen with your own desired assets by replacing the image files in this directory.
+
+You can also do it by opening your Flutter project's Xcode project with `open ios/Runner.xcworkspace`, selecting `Runner/Assets.xcassets` in the Project Navigator and dropping in the desired images.