Issue #1988 results from run-as not working on some phones,
because of Android issue 58373.

This change removes the need for run-as for running
"flutter start". It is still needed for tracing.

wrap up first daemon implementation

This flag builds a local FLX file and pushes that to the device instead of
using an HTTP server.

Instead of just waiting for the sky server process to start
before we start the activity on the device, this causes us to
wait for the sky server to actually start listening on its port

Fixes #141

remove a runInShell arg on windows when launching pub

Windows has no direct way to kill a process based on port. Uses netstats and loops through the results to find the correct process to kill.

Also modify Process.run for the server to runInShell if on Windows.

Style nits.

Now we use a debuggable APK and chmod the installation directory to be world
readable/writable.

Fixes https://github.com/flutter/engine/issues/126

Previous we dumped a stack trace. Now we produce a more sensible error.

This patch adds a couple print statements to explain why the first run of
`flutter start` takes a while. (We need to download the APK and install it on
the device.)

This patch improves the error handling for several arbitrary issues I
encountered while experimenting with the tool this evening.

This patch makes `flutter start` work without a clone of the engine git
repository. Making this work pulled a relatively large refactor of how the
commands interact with application packages and devices. Now commands that want
to interact with application packages or devices inherit from a common base
class that holds stores of those objects as members.

In production, the commands download and connect to devices based on the build
configuration stored on the FlutterCommandRunner. In testing, these fields are
used to mock out the real application package and devices.

Also fixes some minor bugs with iOS and Android interactions.

Don’t give a scary error about not being able to run on Android if there’s no Android device connected.

Just log, don’t exit when the user is missing access to a command. Prevents inappropriately-failing tests.

Also update tests to be compatible with the presence of iOS and add tests for list and install.

Add listen command and basic test, and don’t do unnecessary repeated work when listening or poking the android server.

Also add unchecked runSync wrapper and use it in places where command failures don’t matter.

Refactor all the commands to be Commands from the Args package.  Also use CommandRunner for the top-level command.

`dart bin/sky_tools.dart --debug --sky-src-path=/path/to/sky/src/ install` now works.

This stray line was causing an analyzer error.