Analysis re-work to use analyzer APIs.

It has no more clients.

Follow-up to #3734.

Fixes #2484

* avoid sending analytics on ci systems

* review comments

* Move global analysis options file to the repo root

Also restore the analysis options file for stocks example, since
the global options trigger warnings on generated intl files.

* Remove obsolete analysis options file for Material Gallery example

Previously it used Block, which is less efficient for large numbers of items.
Also move the top margin out of the menu item to fix the baseline alignment of
the text.

Fixes #1615

Fixes #3747

Introduces a new Dart analysis wrapper that works directly with the analyzer API (in favor of shelling out to a separate process).

Some consequences:

  * we no longer need to fear parts (simplifying our dart file gathering)
  * we can filter by error code (when needed), rather than by error strings
  * no more IO scraping
  * no need to generate `main()` or to run with `--package-warnings`
  * we now specify an analyzer (and linter) version in the pubspec (we’ll want to make sure this doesn’t diverge too far from the analyzer shipped with the SDK but it does give us some room to play with experimental builds)
  * no more (re)scanning of error source files (and so no more source cache)
  * should generally be a bit simpler and easier to maintain
  * runs a bit faster :)

Fixes #3741

This patch sizes the menu such that it is always on screen, but doesn't scroll
the menu to ensure that the currently selected item is always visible and on
top of the button. That will need to wait for a later patch.

Also, teach CustomPaint how to repaint animations more efficiently.

Fixes #3720

Prefer implict `equals` matcher in test expectations.

Last literals get their types.

@Hixie: as per our conversation, a little more concise.

This test hangs occationally on the bots and the bots aren't smart enough to
recover, which means the whole project gets blocked.

Filed #3735 about the hang.

Last fixes to get the repo running clean checking for annotations on list and map literals.

Clients of getPosition should just use a one-child custom layout delegate
instead.

Fixes #2484

* First pass at a material-style copy/paste toolbar.

This mimics the toolbar you see when selecting text in an Android
material app. There's still more to do (like integration with the system
clipboard), but this seemed like a good stopping point.

BUG=https://github.com/flutter/flutter/issues/1567

* complain on missing entries in flutter.yaml

* change to a hard failure

More type annotations for literals.

* better parsing of adb devices output

* re-order lines

Fixes #3730

This aligns the analysis options used by 'flutter analyze' with the
options used by Atom.

The `flutter` package gets more types!

Follow-up from: https://github.com/flutter/flutter/pull/3727.

Literals get type annotations.

As per the recent fix to the `always_specify_types` lint (https://github.com/dart-lang/linter/issues/199), literal maps and lists are now expected to be explicitly typed.

Running that lint on the repo identifies quite a few spots to update.  This focuses on `flutter_driver` and `flutter_sprites` (somewhat arbitrarily) but the changes are fairly representative.

Note there are a number of places where I made a quick judgement on how specific to make the types.  Feedback on those is welcome.  (Especially as we move forward with more.)

Turns out we were storing the same object in the base class and the
subclass. For pretty much every AnimatedWidget subclass.

Making progress towards document all public APIs in material.dart. We're still
missing a few odds and ends (as well as missing docs in tabs.dart,
tooltip.dart, and two_level_list.dart).

*  Gallery demo start-time performance test