Closes https://github.com/dart-lang/pub/issues/1556

https://github.com/dart-lang/sdk/issues/31384 was fixed in
https://github.com/dart-lang/sdk/commit/0a6253312f

Available in Dart 2.0.0-dev.12.0

* Retry HTTP requests that are temporarily failing

Closes #1556

This will allow users to play with package features locally without
putting them into the package ecosystem.

We weren't resolving these paths relative to the lockfile location,
which caused "pub global run" to fail for some path packages.

Closes #1751

No plan to ever publish this package

Emit exit code 66 for missing path dependencies

Closes #1747

We were passing an Iterable in place of a List, but an implicit cast
was hiding it from analysis and it worked in practice in unchecked
mode.

Closes #1729

Indicate the source of a dependency in the lockfile

Closes #1721

Closes #1679

See #1723

Closes #1719

This reverts commit 43336bdd.

We're ready to release this feature.

Also introduces the PUB_ALLOW_PRERELEASE_SDK environment variable which can override this behavior. Valid values are `true` (default), `false`, and `quiet` (true but no log message about the override).

Fixes https://github.com/dart-lang/pub/issues/1692

R=jakemac@google.com

Review-Url: https://codereview.chromium.org//3012983003 .

This only applies to package dependencies, not the root package. This is to make it so the sdk constraint doesn't become a required field for all pubspecs in 2.x sdks.

A future update will make it so publishing a package requires an upper bound sdk constraint. 

* added overridable field 'featuresEnabled' for testing as well

Fixes https://github.com/dart-lang/sdk/issues/30246

As of https://github.com/dart-lang/sdk/commit/5b29ae48adcadc6f5f98c6ee937d4bb7c8414c83 the analyzer_cli no longer records summary deps, so the summary test started failing.

Fixes https://github.com/dart-lang/pub/issues/1687

fixes https://github.com/dart-lang/pub/issues/1684

Add "pub run --list" command to show all available executables #2

* removed "run --list" command
* buffer is used to output executables
* tests were adapted to verify --dev/--no-dev flag

This reverts commit 3e4890f1.

Does not fix https://github.com/dart-lang/pub/issues/1666
Tracking internally here http://b/63855519

Fixes https://github.com/dart-lang/pub-dartlang-dart/issues/230

* Fix deprecated uses from cli_util
* Move analysis_options to the correct name