Rather than managing all the Material Design icons manually, we now
manage them using an icon font. The icon font contains glyphs for each
icon in an efficient vector format.
This patch updates the FLX tooling to include the MaterialIcons font and
updates the Icon widget to use the font instead of asset images.
Fixes#2313Fixes#2218Fixes#2009Fixes#994
Runs a test app and a driver test simultaneously, then stops the app.
Usage:
```
flutter drive --target=/path/to/test/app.dart
```
This command will look for `/path/to/test/app_test.dart` by
convention. We will expand into other ways of discovering tests in the
future.
This splits flx.build() into two methods, flx.build() and
flx.assemble(). builD() now does the following:
1) constructs the manifest map by reading the manifest from the
file system
2) "compiles" the dart code into the snapshot file
3) Invokes assemble()
This allows external build toolchains to construct their own
manifest map (possibly using a different manifest syntax)
and create their own snapshot file
