update a field ref in playfair

Execute rename fixit (Part 2)

* justifyContent -> mainAxisAlignment
* alignItems -> crossAxisAlignment
* FlexJustifyContent -> MainAxisAlignment
* FlexAlignItems -> CrossAxisAlignment

Fixes #231

Removes an LTR bias in DismissDirection.

Fixes #2562

* left -> leading (Removes an LTR bias)
* center -> title (Widget was actually centered)
* right -> actions (Removes an LTR bias, asymmetric with leading)

Fixes #2348

The terms "left" and "right" have an LTR bias. Instead, we now use
"leading" and "trailing", for these list and grid decorations so that
we can later rearrange them to match the reading order.

Fixes #2540
Fixes #2548

Fixes #2448

Fixes #2353

rename the platform constants

Execute rename fixit

This patch renames StatelessComponent to StatelessWidget and
StatefulComponent to StatefulWidget.

Fixes #2308

Fixes #2233

Fixes #1482

Fixes #1382

Fixes #1278

Fixes #774

Fixes #581

Fixes #459

Also, change the keys to be explicitly pointer ids.

Fixes #202

add an atom launch config to the starter app

fix a regression in adb forward

fix a launch issue when the user has deleted the app

Enable always_specify_types lint

And fix the zillion issues that uncovered.

Revert "Merge pull request #2639 from Hixie/always_specify_types"

This reverts commit f41b3411, reversing
changes made to e33d8d96.

This was a bad check-in due to my mangling uploading a new version of the branch from a different machine.

This reverts https://github.com/flutter/flutter/pull/2639 and will be replaced by https://github.com/flutter/flutter/pull/2640

Almost enable always_specify_types lint

Enable strong mode again.

And fix the zillion issues that uncovered.

Handle the case of reparenting while updating children

Instead of trying to flush the detached children from the child list, we keep
the set of detached children up to date and query on every read.

show the error codes in flutter analyze --watch