Fix version conflicts, verify publishability of packages in CI, Remov…

…e Travis (flutter#729)

This fixes a number of version resolution errors that would prevent these packages from building, and turn off Travis, since Cirrus now works.

I also fixed a number of errors that would have prevented these packages from being published without warnings, and establishes a CI script that will verify publishability for any changed packages in a PR.

For some examples, we were depending upon versions of other 1st-party plugins by using path: ../../<package>, which really isn't the right way to do things, so for those examples, they now depend on a published version.

I bumped the version number of any packages that were modified, and updated their CHANGELOGs since the dependencies have changed.

Also fixed a number of analyzer errors that somehow snuck in.

CHANGELOG.md

@@ -1,3 +1,8 @@
+## 0.2.3
+
+* Added path_provider and video_player as dev dependencies because the example uses them.
+* Updated example path_provider version to get Dart 2 support.
+
 ## 0.2.2
 
 * iOS image capture is done in high quality (full camera size)

example/pubspec.yaml

@@ -1,13 +1,14 @@
 name: camera_example
 description: Demonstrates how to use the camera plugin.
+author: Flutter Team <flutter-dev@googlegroups.com>
 
 dependencies:
-  path_provider: 0.3.0
-  flutter:
-    sdk: flutter
   camera:
     path: ../
-  video_player: "0.5.2"
+  path_provider: ^0.4.1
+  flutter:
+    sdk: flutter
+  video_player: ^0.5.2
 
 dev_dependencies:
   flutter_test:

pubspec.yaml

@@ -1,7 +1,7 @@
 name: camera
 description: A Flutter plugin for getting information about and controlling the
   camera on Android and iOS. Supports previewing the camera feed and capturing images.
-version: 0.2.2
+version: 0.2.3
 authors:
   - Flutter Team <flutter-dev@googlegroups.com>
   - Luigi Agosti <luigi@tengio.com>
@@ -15,6 +15,10 @@ dependencies:
   flutter:
     sdk: flutter
 
+dev_dependencies:
+  path_provider: ^0.4.1
+  video_player: ^0.5.2
+
 flutter:
   plugin:
     androidPackage: io.flutter.plugins.camera