Previously, EditableString had many public members because it needed to
implement the KeyboardClient interface. However, that's confusing
because these methods cannot be called directly.

Now EditableString holds a private implementation of the KeyboardClient,
which hides the implementation details.

Fixes #208
Fixes #209

improve device notification support

Keyboard service doesn't commit the last edit when it's dismissed

We were getting the proper values, but we thought we were still composing, so
the text was still underlined.

Fixes #115

Support local paths to third-party jars in flutter apk.

Improve error messages for iOS workflow

This reverts commit b240cda8.

We now check that you've got an "ios" directory and that you have the proper
version of Xcode.

Also improve the error message a bit if a download fails.

get a bug fix for multi-line command descriptions

_getPadding was ignoring its argument

Reimplement Inherited.notifyDescendants to use a registration list

...instead of a deep walk.

Add material design features to Input

That way folks can customize it if they want (and it makes the code a
bit more self-documenting).

Now the label animates from its inline position to above the text and
the focus highlight grows into place.

RawEditableLine is now responsible for the scrolling behavior, which
removes the need for callbacks between RawEditableLine and Input. It
also fixes a bug whereby the whole Input widget (including its icon)
would scroll when the text got long.

Properly support labels, hints, icons, and custom typography.

This reverts commit ab300634.

Make `flutter list` not crash on linux.

Turns out linux does have an ideviceinstaller package
however it doesn't contain idevice_id or any of the
other tools we use.  Furthermore we don't have
xcrun or the rest of xcode on linux so we can't
manipulate simulators either.

No sense in printing out a warning that ios isn't supported
every time on linux, so I wrapped that block in osx only.

@chinmaygarde @devoncarew

Add the ability to lose focus

Fixes #1308

Input widget shrinks when typing a space

This patch restructures how we size the editing region of the Input widget. Now
RenderEditableLine understands that it's a single-line editing widget and sizes
itself correctly.

Simplify colorizing icons

Now you can colorize an Icon simply by proving a Color for the Icon.

Refactor device.dart

remove device type specific checks

'flutter apk' now supports dynamically registered services.

Third-party libraries can now provide their own mojo services. They do
so by adding a config.yaml file to their pub package which contains
- a list of service names and java classes which handles that service's
  registration.
- a list of pre-built .jar files to statically link with the app's shell
  when building the app.

Change Block children to be a named parameter

This is a backwards incompatible change.

Added TwoLevelList et al, a Material Expand/Collapse List Control

A TwoLevelList can can contain TwoLevelListItems, essentially ordinary list items, or TwoLevelSublists which have a list of items of their own. Tapping on a TwoLevelSublist causes it to expand, showing its items. Tapping again causes it to collapse.