* add web server device

* remove extra async

* fixes to server device

* testing updates

* fix test cases

* address comments

Needed for Fuchsia roll.

* Discover port over mDNS 

* Update BUILD.gn for tools

Need for roll into Fuchsia

Pull code out of flx.dart:assemble() to make flx.dart:buildAssets
which creates the AssetBundle. This will allow us to create just
this instead of an entire FLX.

Fuchsia will soon use a newer version of the Dart analysis server which Flutter code has not been adjusted for yet.

This affects the Fuchsia build which will soon run analysis by default.

This package now depends on collection and quiver. The package level
dependencies in the BUILD.gn file should match the list of dependencies
in the pubspec.yaml file for the Fuchsia build to function.

This package depends on package:process now.

We're getting rid of the http package from third_party/dart-pkg/