Our supressions for the generated mojom.dart files weren't working after we
deleted the mojom package. This CL updates the filters to catch mojom.dart
files again.

Remove sky:init

Now that we don't have a magicaly mojom package, we don't need sky:init.

Support borders with borderRadius

Add transitions.dart for common animation transitions.

Use those in SnackBar, Drawer, navigator instead of AnimatedContainer's
intentions.

Currently we support only borders with uniform color and width.

Use absolute URLs in sky/packages/sky/README.md

When this README.md is published to pub.dartlang.org, the base URL is
pub.dartlang.org. We need to use absolute URLs in order to get back to GitHub.

Fixes #417

Fix TextAlign.right

We were applying the style to the RenderInline but we actually needed to apply
it to the RenderParagraph. The lineHeight property had the same problem.

Make sky package depend on new sky_engine and sky_services

Don't upload things again in stage two

Bump versions of sky packages

Add a --stage-two to big_red_button.py

Bump Dart runtime dependency

Stacked does not repaint when its position changes

Do not invoke mojom/generate.dart from sky_tool anymore

Bump sky package version requirements

We were marking the parent *Widget's* render object as needing layout, but
we actually need to walk up the component tree until we find the parent
*RenderObjectWrapper* so we can mark actually mark the parent render object as
needing layout.

Fixes #408

Make it possible to pass a URL via command line to Mac SkyShell.app

@chinmaygarde

Add --enable-checked-mode to sky_shell

Simplify Navigator's Transition code a bit.

Fixes anchor points for particles in particle systems