Switch to use browser/dart.js (fix #300)

Review URL: https://chromiumcodereview.appspot.com//12079051
Update CHANGELOG.md
Push a new version with the latest features (includes printing warnings again)

Review URL: https://chromiumcodereview.appspot.com//12084070
fix for breaking html5lib change

Review URL: https://chromiumcodereview.appspot.com//12087111
fix #304 - better warnings for missing script type

Review URL: https://chromiumcodereview.appspot.com//11878012
Fixing bug in the evaluation order of watchers

Review URL: https://chromiumcodereview.appspot.com//12162005
Update CHANGELOG.md
keep track of pending paths and ignore dupicates to fix #336

_pending shoud not be cleared until the flushed Futures complete; and we
check _pending from writeString() before setting up an
open->write->close future chain on it.  This solves the case of multiple
parallel writes to the same file with the same contents.
we remove() from _pending in the continuation after we close() the file

this means we don't need to clear _pending from flush(); in flush() we
do a toList() on the values Iterable to guarantee we won't be removing
from our active iterator
Merge pull request #345 from rmsmith/master

keep track of pending paths and ignore duplicates to fix #336
Use whenComplete so the condition runs even in error case.

Review URL: https://chromiumcodereview.appspot.com//12181020
Fixes for next sdk

Review URL: https://chromiumcodereview.appspot.com//12181004
Print unit in the output of perf.dart

Review URL: https://chromiumcodereview.appspot.com//12186027
Add sdk dependency to pubspec

Review URL: https://chromiumcodereview.appspot.com//12208015
include revision in sdk constraint
Replace mappedBy with map (mappedBy will be removed in the future).

Review URL: https://chromiumcodereview.appspot.com//12221034
Fix web-ui to use source_maps spans.

Review URL: https://chromiumcodereview.appspot.com//12210053
Update CHANGELOG.md
Update the webui dartium extension

Review URL: https://chromiumcodereview.appspot.com//12221076
fix #318 - use web-ui-dev@dartlang.org list

This new list is for discussing development of web-ui