Update sample and docs links
deprecate package:js in favor of dart:js
clarify why the move to dart:js is important
make this a breaking change
Merge pull request #150 from sethladd/redirect-to-dartjs

Redirect to dartjs
Delete almost everything in prep for rewrite.
Initial check in of basic classes:
Adds metadata classes, JsInterface, the library
transformer, library scanner, and proxy generator.
New abstract class / impl design
Add .pub to .gitignore
Add a dynamic (mirrors) implementation of typed interfaces.
Add js_elements AST library, and JsInitializerExporter to export initialization calls.
Update version to 0.4.0
Add EntryPointTransformer to call initialization methods
Add fake package to run transformed tests on.
Add JsInitializerGenerator
Add a mirrors-based implementation of exports.
Add a few more exports test.
Fix some generated code issues.
Add HtmlTransformer to replace interop.js script tag.
Support exporting multiple Dart libraries with the same prefix.
Enclose JS initialization in function expressions.
Don’t export JsProxies or abstract classes.
Fix some issues in the previous CL.
Remove mirrors imports in transformed code.
Update version number in README