android screenshare example and touch ups (#31)

example/pubspec.lock

@@ -90,6 +90,13 @@ packages:
     description: flutter
     source: sdk
     version: "0.0.0"
+  flutter_background:
+    dependency: "direct main"
+    description:
+      name: flutter_background
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.0.2+2"
   flutter_lints:
     dependency: "direct dev"
     description:
@@ -218,6 +225,20 @@ packages:
       name: path_provider
       url: "https://pub.dartlang.org"
     source: hosted
+    version: "2.0.7"
+  path_provider_android:
+    dependency: transitive
+    description:
+      name: path_provider_android
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "2.0.6"
+  path_provider_ios:
+    dependency: transitive
+    description:
+      name: path_provider_ios
+      url: "https://pub.dartlang.org"
+    source: hosted
     version: "2.0.6"
   path_provider_linux:
     dependency: transitive
@@ -225,7 +246,7 @@ packages:
       name: path_provider_linux
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.1.0"
+    version: "2.1.1"
   path_provider_macos:
     dependency: transitive
     description:
@@ -246,7 +267,7 @@ packages:
       name: path_provider_windows
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.0.3"
+    version: "2.0.4"
   petitparser:
     dependency: transitive
     description:
@@ -302,7 +323,7 @@ packages:
       name: shared_preferences_linux
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.0.2"
+    version: "2.0.3"
   shared_preferences_macos:
     dependency: transitive
     description:
@@ -330,7 +351,7 @@ packages:
       name: shared_preferences_windows
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.0.2"
+    version: "2.0.3"
   sky_engine:
     dependency: transitive
     description: flutter
@@ -419,7 +440,7 @@ packages:
       name: win32
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.2.10"
+    version: "2.3.0"
   xdg_directories:
     dependency: transitive
     description: