Various clean-up.
Make settings dialog slide in, instead of being modal.
Copy caching compiler from dart2js tests.
Update leap_server to serve current version of Try Dart!
Prepare for Modifier-Down.
Add 'breakpoint' similar to 'debugger' from JavaScript.
Fix bug which caused type warnings to be displayed a incorrect positions.
Better progress for --analyze-all.
Update leap_server.dart to serve the sources of Try Dart!
Use org-trydart:, not memory:.
Support showing Try Dart! sources instead of examples.