add support for template repeat

it's identical with template element, but with template attribute it adds additional capabilities and should work more conveniently in cases like <td> and <option>

Review URL: https://chromiumcodereview.appspot.com//13592003
add test for style and text mode

Review URL: https://chromiumcodereview.appspot.com//13529024
fix #445 - observe used by doc comment was shadowing the function

Review URL: https://chromiumcodereview.appspot.com//13427017
release 0.4.5 (update pubspec and changelog)
example tweaks
Merge pull request #452 from kevmoo/master

Tweaks to TODO MVC example
add $index, fixes #277

Review URL: https://chromiumcodereview.appspot.com//13915003
TODO MVC - while I'm at it
Merge pull request #453 from kevmoo/master

TODO MVC: while I'm at it...
Readme fixes

Closes #455
Points to new github.io domain for gh-pages
Added self to AUTHORS
fixed analysis errors in explainer code
explainer: fixed reference to bootstrap css
Merge pull request #457 from kevmoo/explainer_fixes

Explainer fixes
Merge pull request #456 from kevmoo/master

Readme, author fixes
fix two way binding for selectedIndex and other fields
In general, we were quite confused about bind- fields, since they were added to the "attributes" dictionary but they had already been camelCased.

Review URL: https://chromiumcodereview.appspot.com//14121018
Upgrading web_ui to 0.4.6

Review URL: https://chromiumcodereview.appspot.com//13999004
fixes for latest sdk

Review URL: https://chromiumcodereview.appspot.com//13845018
hot fix - use latest html5lib
minor tweaks to run.sh.
 - the new 'dartanalyzer' doesn't create the work directory
 - minor changes in printing and grouping messages in the output

Review URL: https://chromiumcodereview.appspot.com//13877011
Revert change on clearning directories until we fix dependency between
render_tests and html5_util_test

Review URL: https://chromiumcodereview.appspot.com//14053017