Make outline view resizable + improve outline toggle button

Scrolling in the ouline view is out of sync
Merge remote-tracking branch 'upstream/master' into resizable-outline-and-better-button

Conflicts:
	ide/app/spark.dart
Merge remote-tracking branch 'upstream/master' into resizable-outline-and-better-button
Fix scrolling synchronization for good, supposedly
Fix typo in prev commit
fix a cce in pub
Significant rewrite: single coordinate system, flat item list, no artificial scroll target
OutlineItems self-add to passed down Outline.outlineItems

Symmetry with OutlineClass adding its members + control over which items get added and in what order (important for searching in the now flat outlineItems).
Clip incorrect offset ranges for class top-node and ctor to their true sizes

As provided by Ace (?), they both span the entire class's definition (for constructors, it's likely a bug), which is not what we want when highlighting or scrolling them into view.
Remove debugging stuff
Improve gitRef code.
More cleanup and refactoring.
Write remoteRefs whenever fetched.
Fix bug in creating refPaths.
Add support to update remoteRefs in fetch
Update remoteHead async, when requested.
More cleanup.
fix.
Remove old remote refs when updating.
Bug fixes to commit before last