Support package build_runner

• Add support for package build_runner.
• Material Auto-Suggest Input:
  • Wait for the popup to be visible before activating dropdown items.
  • Stop escape keyboard events from propagating after they are handled.
  • Disallow deselection when clicked on a selected item with single selection
  • models.
  • Ensure input text is initialized correctly regardless of input order.
  • Fix auto-scrolling issue on Firefox.
• Material Checkbox: Make focusable.
• Material Fab: Update shadow styles.
• Material Input: Don't override underline color when the input is invalid.
• Material Menu: Add button content customization.
• Material Radio: Update disabled color to match spec.
• Material Select:
  • Wait for the popup to be visible before activating dropdown items.
  • Stop escape keyboard events from propagating after they are handled.
  • Fix MaterialSelectItem displaying two times the label when
    factoryRenderer is used.
  • Fix auto-scrolling issue on Firefox.
• Material Tab: Add two-way binding on fixed strip activeTabIndex.
• Material Tree: Autofocus the filter when MaterialTreeDropdown is opened,
  but not when it closes.
• Better support for the zippy expansion case in selection model.
• Deprecate getBool, angular supports it now natively.
• Fix RTE when using item renderers as highlight renderers when there is a
  custom factory renderer.
• Fix componentRenderer logic.
• Add option to disable select all in the table selection model.
• Add a feature detector for position: sticky.
• Migrate from Glyph to Material Icon.
• Remove unused table model.
• Remove the getDynamic method from properties helpers.
• Remove uses of .runtimeType.
• Fix uses_bottom_as_dynamic ("fuzzy arrow") errors.
• Cleanup unneeded preserveWhitespace: false and preserveWhitespace: true.
• Cleanup type warnings and other Dart 2.0 fixes.
• Cleanup unused variables.
• Update documentation.