v0.9.1

Component Updates

Material Date Range Picker

• Add an option to disable maintaining the length of the date range when
  clicking on the calendar to move the start date.

Material Expansion Panel

• Add Sass mixin for border radius.
• Only register immediate child panels in a panel set.
• Add listener for expand change to fix bug where an expansion panel set would
  not recognize a programmatically pre-expanded panel.

Material Select

• Add Sass mixin for the selected item color.

Material Stepper

• Add Sass mixins for the step name color.

Material Toolip

• Add Sass mixin to set the card tooltip max width.
• Add an icon attribute to specify any icon by name.
• Add positioning options on icon tooltip.

Selection Options

• Add interface to segment options into option groups.

Miscellaneous

• Fix ActiveItemDirective's scroll into view functionality in popups and
  modals.
• Add ObservableView.firstNonNull and ObservableView.nonNullValues.
• Update MDC Web styles to v0.38.0.
• Fix missing return errors.
• Fix default line-height values to match MDC versions.

Documentation

• Minor doc fixes.
• Cleanup some docs for with optional new/const.