Target armv7 when the dart_target_arch is forced to be arm (vs arm64)

Extract jinja template rule from Android specific rules

Move sky_snapshot to the correct place

Improve error handling in sky_snapshoter

Now we print a more sensible error message and exit with an error instead of
appearing to crash.

Fixes https://github.com/flutter/flutter/issues/53

Update CONTRIBUTING.md to account for flutter.git

Remove Dart packages which have moved to flutter.dart

Add flutter.yaml for address_book example

Fix SnapshotterInvoke to look for the correct path to dart_service_isolate in pub cache

Don't crash if no widthFactor is set in an unbounded context

We throw an exception if you tap the screen during load

Roll mojo

Only make Xcode run the snapshotter and packager if the project is updated between builds

Provide the location of dart:vmservice_sky to the precompilation snapshotter

Inside runApp, we were building the render tree for the app, but we weren't
calling layout, which meant we were running a hit test on a dirty tree. Now
hitTest specifically asserts that the tree is clean and we synchronously call
layout for your app during runApp.

Fixes #1960

Publish service isolate dart files to sky_engine/sdk_ext

clarify flutter is early-stage

Heroes don't reverse any more

We need to use the performance for the "from" route when going backwards. Also,
fix a bug in the HeroParty where it would call the quest finished callback
multiple times.

Fixes #1958