Update documentation for RandomAccessFile

R=kustermann@google.com, lrn@google.com
BUG=http://dartbug.com/21516

Review URL: https://codereview.chromium.org//702363002

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@41548 260f80e4-7a28-3924-810f-c04153c831b5
Mark test failing due to dartbug.com/21523

Review URL: https://codereview.chromium.org//706883002

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@41549 260f80e4-7a28-3924-810f-c04153c831b5
Encode super calls via extra properties on prototypes.

BUG=
R=floitsch@google.com, sra@google.com

Review URL: https://codereview.chromium.org//693883003

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@41550 260f80e4-7a28-3924-810f-c04153c831b5
Fix type warning in dart:async.

Review URL: https://codereview.chromium.org//705963002

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@41551 260f80e4-7a28-3924-810f-c04153c831b5