Fix http://dartbug.com/21335
- Make the VM internal AssertionError, TypeError and CastError implement
  the public classes instead of patching them.

R=asiva@google.com, lrn@google.com

Review URL: https://codereview.chromium.org//669733004

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@41231 260f80e4-7a28-3924-810f-c04153c831b5
change icon/message for add package

R=danrubel@google.com

Review URL: https://codereview.chromium.org//667903005

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@41232 260f80e4-7a28-3924-810f-c04153c831b5
Add unboxed Mint for X64

BUG=
R=vegorov@google.com

Review URL: https://codereview.chromium.org//626223002

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@41233 260f80e4-7a28-3924-810f-c04153c831b5