include imported elements in interpolation suggestions

BUG=
R=scheglov@google.com

Review URL: https://codereview.chromium.org//646773002

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@41032 260f80e4-7a28-3924-810f-c04153c831b5
Ignore case when sort members.

R=brianwilkerson@google.com, danrubel@google.com
BUG=

Review URL: https://codereview.chromium.org//646753002

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@41033 260f80e4-7a28-3924-810f-c04153c831b5