add explicit paths to the flutter recipies

Analyze CLI option to specify a custom Dart SDK.

Handy for testing against specific local SDK builds.

(Note that the option is hidden.)

* download android-arm-deploy

* wire up --deploy to android-arm-deploy

* fix interpolation

* use the new cache code to locate more artifacts

* add todo

* review comments

* find all repo packages

* .dartignore

+ Add new demo to gallery to show data tables. (This currently doesn't
use a Card; I'll create a Card version in a subsequent patch.)

+ Fix checkbox alignment. It now centers in its box regardless.

+ Add Colors.black54.

+ Some minor fixes to dartdocs.

+ DataTable, DataColumn, DataRow, DataCell

+ RowInkWell

+ Augment dartdocs of materia/debug.dart.

+ DropDownButtonHideUnderline to hide the underline in a drop-down when
  used in a DataTable.

+ Add new capabilities to InkResponse to support RowInkWell.

+ Augment dartdocs of materia/material.dart.

+ Add an assert to catch nested Blocks.

+ Fix a crash in RenderBox when you remove an object and an ancestor
  used its baseline. (https://github.com/flutter/flutter/issues/2874)

+ Fix (and redocument) RenderBaseline/Baseline.

+ Add flex support to IntrinsicColumnWidth.

+ Document more stuff on the RenderTable side.

+ Fix a bug with parentData handling on RenderTable children.

+ Completely rewrite the column width computations. The old logic made
  no sense at all.

+ Add dartdocs to widgets/debug.dart.

+ Add a toString for TableRow.

Fixes https://github.com/flutter/flutter/issues/3363

Fixes https://github.com/flutter/flutter/issues/3352

If two repaint boundaries mark themselves dirty, but the second one is a
child of the first, then the second one will get repainted by the first
and then when we come to paint it directly, we get confused because it
isn't dirty any more.

We ran into this in layout before. Apply the same fix. Also, apply the
same fix to composition while we're at it.

Add a Performance Overlay toggle to the Gallery app

Exception stack variable was shadowing the function argument stack.

We're getting back to the point where we have a bunch of foundation APIs
and it's getting confusing having them mixed with services/.

Make update-packages cover dev/benchmarks.

update-packages only looks one level down, instead of
changing that, I'm just adding dev/benchmarks explicitly.

This will unbreak the bots which are dying trying to
flutter drive dev/benchmarks/complex_layout without
pub get having been run there.

@yjbanov @devoncarew

...even if the test fails.

until we have a fix for the breaking changes

Adding `@optionalTypeArgs`.

With the new dev build we've got the updated linter and so can use the `@optionalTypeArgs` annotation (in `meta 0.12.0`).

Bonus: this lets us clean up one more Regexp in the `analyze` command! :)

Add a basic scrolling test for the Gallery home page.

Repaint child view on attach / detach.

* run pub for analyze and test

* don't run pub when doing repo analysis

* move logic for when to run pub into the commands

* re-write ternary expression

* Improvements to the Grid list demo

* More nits and fixes to grid demo in gallery