We now just symlink the lib directory into the packages directory in the output
directory.

This CL introduces a SkyShell.apk that is separate from the SkyDemo.apk that we
upload to the store to show our demos.  The SkyShell.apk is just an empty shell
that can run Sky applications on Android.

The Python HTTP server was caching too agressively. Instead, use an HTTP server
written in Dart from the sky_tools package.

Instead, just use a normal http URL.

- Pub doesn't publish dot files (who knew?!)
- sky_tool was referencing a variable that doesn't exist

R=abarth@chromium.org

Review URL: https://codereview.chromium.org/1223173003 .

Previously we defaulted to main.dart, which was confusing. Now we default to
the current working directory, which is more understandable. As part of this
change, I've also changed the default location of main.dart to lib/main.dart,
which makes our current examples.

Fixes #274

R=eseidel@chromium.org, eseidel@google.com

Review URL: https://codereview.chromium.org/1215103006.

Fixes #275

R=eseidel@chromium.org, eseidel@google.com

Review URL: https://codereview.chromium.org/1216283003.

We now have to run mojom/lib/generate.dart before we
can launch a sky app. :(

Fixes https://github.com/domokit/mojo/issues/262

R=johnmccutchan@google.com

Review URL: https://codereview.chromium.org/1205623002.

Update sky_server:
 - update its help string to admit that it wants the package path as well.
 - be quiet by default, since it makes the build chatty.
 - have a -v for verbose mode, for people who like it chatty.
 - have a default port of 8000, since that's what everyone used.
 - have a -p option to set the port, for people who don't use the default.
 - remove its mapping for gen/, since a TODO told me to.
 - remove the dependency on the build configuration, since it's no longer used.
 - teach it about .dart files.
 - rename sky_server/README to README.md, for consistency with other READMEs.
Update shelldb to speak the new sky_server protocol.
Update tests/services/iframe-embed-vmc.sky since the sky_server change broke the hack it was using.
Update skyserver.py to speak the new sky_server protocol.
Make webkitpy use SkyServer instead of spawning sky_server itself, since a TODO told me to.
Teach webkitpy about dart files.
Teach test_perf about dart files. (untested)
Teach sky_tool about main.dart, main.sky is deprecated. (untested)

R=eseidel@chromium.org

Review URL: https://codereview.chromium.org/1200993002.

NOTE: This CL appears far larger than it actually is for two reasons:

1) Many files were moved around to use the Dart package directory structure.
2) Many .dart files had to have import paths updated.

- Organize mojo/public/dart so that it uses standard Dart package layout
- Organize mojo/dart/apptest so that it uses a standard Dart package layout
- Organize sky/sdk so that it uses a standard Dart package layout
- Create a mojo/testing package (used by unittests)
- Introduce the 'dart_pkg' gn rule which populates gen/Config/dart-pkg
- All internally vended Dart packages must have a corresponding dart_pkg rule
- It is now possible to use dependency_overrides: in pubspec.yaml to mix internal and external package dependencies (enables analyzer, editor, webstorm usage for internal developers).
- Package root for dart content handler ends with "packages/"
- Imports of mojo package uris no longer need the "public/dart"
- mojo/public/tools/dart_package.py is a clone of mojo/public/tools/gn/zip.py
- Sky tests no longer run 'deploy_sdk' script.

R=eseidel@chromium.org

Review URL: https://codereview.chromium.org/1132063007

TBR=ianh@google.com

Review URL: https://codereview.chromium.org/1114553004

Also fixed missing entry in CHANGELOG.md

TBR=ianh@google.com

Review URL: https://codereview.chromium.org/1108393003

This is just copy-pasted from shelldb but should work.

TBR=ianh@google.com

Review URL: https://codereview.chromium.org/1112433003

This will require me to roll the sky pub package, sigh.

R=ianh@google.com

Review URL: https://codereview.chromium.org/1090713002

Just silly fixes needed for our 4 copies of our python run script.

R=ianh@google.com

Review URL: https://codereview.chromium.org/1064983003

I'm not sure this is the final long-term solution, but works for now.

R=abarth@chromium.org

Review URL: https://codereview.chromium.org/1022193002

TBR=abarth@chromium.org
BUG=

Review URL: https://codereview.chromium.org/1021933004