Built test bar into editor and setup periodic test for styling of animation.  Will strip out and raise in the hierarchy to application level.
Setup dialog for toast on top of app.  Temporary test on app start.
Removing editor level toast and test
Moved the progress toast to the top of the page and removed app-start test
Wired up the progress toast to start after 500 ms of waiting for navigateToDeclaration()
Dismiss progress toast after completion of navigateToDeclaration(...).  Fixed SparkPolymerDialog.hide() to not always toggle.
Cleaned up, styled, and prepared for PR
Dynamicized the toast so custom messages can be passed when invoked.
Removed modal-title and replaced with parent specific title
Tidied up html
Review fixes, and renamed El --> Element for clarity
Merge branch 'umop-linking-progress_indicator' of https://github.com/dart-lang/spark into umop-linking-progress_indicator
Review fixes: Removed top modal toast and replaced with bottom status message on timeout or no-declaration
Placing the timeout within navigateToDeclartion call in ace.dart, but catchError is not catching the TimeoutError
Fixed timeout() placement to timeout before navigation.  Cosmetic fix that was accidentally reverted)
Merge pull request #2003 from dart-lang/umop-linking-progress_indicator

Linking progress indicator for long operations