Multiple improvements, but not 100% NewUI yet
Merge remote-tracking branch 'upstream/master' into new-ui-button

Conflicts:
	widgets/lib/spark_button/spark_button.css
Delete spark-icon-button - spark-button will be able to do the same thing
Merge remote-tracking branch 'upstream/master' into new-ui-button
Delete spark-icon-button test
Merge remote-tracking branch 'upstream/master' into new-ui-button

Conflicts:
	widgets/lib/spark_button/spark_button.css
Merge remote-tracking branch 'upstream/master' into new-ui-button
Minimize the button test for now
Globally turn off outline for widgets and widget's contents
Remove spark-icon-button from top-level examples.dart
Workaround to ensure propagation of changes from spark-menu-button to spark-button
Merge remote-tracking branch 'upstream/master' into new-ui-button
Merge remote-tracking branch 'origin/new-ui-main-menu' into new-ui-button
Merge remote-tracking branch 'origin/patch-new-dartium-problems' into new-ui-button
Merge remote-tracking branch 'upstream/master' into new-ui-button

Conflicts:
	widgets/lib/spark_menu_button/spark_menu_button.dart
Merge remote-tracking branch 'upstream/master' into new-ui-button
Merge remote-tracking branch 'upstream/master' into new-ui-button
Major redesign of spark-button

Different look & feel, different attributes.
Merge remote-tracking branch 'upstream/master' into new-ui-button
Switch to a more standard place to handle/set initial attribute values