Implemented scrolling
Cleaned up implementation (scrolling)
Organized a bit for style
Temporary commit before merge to get deactivate (overriding activate)
Merge branch 'master' of https://github.com/dart-lang/spark into umop-outline-remember_position
Overriding activate and deactivate to store outline scroll position
Just recording the scroll position instead of listening for all scroll events
Merge pull request #1752 from dart-lang/umop-outline-remember_position

Outline: Remember position of current file