Removed the legacy --plugin option from flutter create.  Fixes #11815.

Allows the user to specify the kind of project to create. The default is 'app'. Other choices are 'plugin' (the old '--plugin' behavior), and 'package'.

A Flutter 'package' is a Dart package that depends on Flutter, but does not contain native code.

Fixes #10377.

This reverts commit 8d07d3f6.

Fixes #10077

* Enforce valid package names on flutter create

Fixes #9564

* refactor

* fix other tests

* Don't crash on `flutter create .`

Fixes #9828

* review comments

Eagerly generate local.properties, and always update the flutter.sdk
setting in it, in case FLUTTER_ROOT has changed.

Fixes #8365.
Fixes #9716 - at least the specific issue reported. My Android Studio
still complains about Gradle versions - it ships with v3.2, but requires
v3.3...

Add a 'generate dependencies' task to the Gradle build, which checks if
the snapshot dependencies file exists, and runs an extra build before
the actual FlutterTask if it doesn't. This makes the first build slower,
but sub-sequent builds (without source changes) much faster.

Fixes #9717.

* Remove all initial cocoapod traces from flutter create except Podfile

* Make updateXcodeGeneratedProperties parameters named

* review notes

When invoked from the command line, relative paths aren't typically
used, but they are when invoked from within IDEA and prevents
IDEA from reading the files.

Also, remove flutterPackagesDirectory since it's not used

Generates an android.iml file and a package-level library for flutter.jar.

Does not set up an Android SDK in IDEA; this isn't possible with a
template-based approach. But IDEA shows a clear warning, so the
user can fix this by setting the SDK.

(When creating a Flutter project from within IDEA, we can fix this up
afterwards in the plugin.)

Added a PluginRegistry to the new project template. The registry files will be automatically updated at build time to register the native plugins.

Fixes #7814.

Plugin projects are created by running `flutter create --plugin <name>`.

An example app is also created in the plugin project, using the normal 'create' template, which has been modified to allow for conditional plugin code.

Modified the android package name to match package naming conventions (all lower-case, and must match the directory name).

On flutter run, we update ios/Flutter/Generated.xcconfig with various
Flutter-specific settings required by xcode_backend.sh during a build
from Xcode. These settings need to be present at the time the project is
loaded since Xcode doesn't pick up live updates to these files.

Without these settings, Xcode fails to locate xcode_backend.sh itself,
causing the build to fail until the Xcode project has been closed and
re-opened. This also prevents Xcode's project updater from 'helpfully'
suggesting to clean up and delete the Generated.xcconfig file.

This removes direct file access from within flutter_tools
in favor of using `package:file` via a `FileSystem` that's
accessed via the `ApplicationContext`.

This lays the groundwork for us to be able to easily swap
out the underlying file system when running Flutter tools,
which will be used to provide a record/replay file system,
analogous to what we have for process invocations.

* Remove the workaround that pinned args to v0.13.6
This reverts most of the changes in commit 6331b6c8
* throw exception if exit code is not an integer
* rework command infrastructure to throw ToolExit when non-zero exitCode
* convert commands to return Future<Null>
* cleanup remaining commands to use throwToolExit for non-zero exit code
* remove isUnusual exception message
* add type annotations for updated args package

* convert flutter commands to use ToolExit for non-zero exit code
* add convenience method throwToolExit
* print ToolExit message iff not null

Fixes #6417

Fixes #6480

Previously it implied that you had to always say lib/main.dart in the "flutter run" command.

* make flutter create less chatty

* output generated file count; mention lib/main.dart

* refactor _run to runCmd

* replace requiresProjectRoot getter with call to commandValidator

* replace requiresDevice getter with call to findTargetDevice

* trace command requires a debug connection, not a device

* inline androidOnly getter

* rename command methods to verifyTheRunCmd and runCmd

* move common verification into BuildSubCommand

* rename deviceForCommand to device

* rename methods to verifyThenRunCommand and runCommand

* show device list in flutter doctor output
fixes https://github.com/flutter/flutter/issues/5625

Fixes #3835