Classes: Add support for toString

BUG=v8:3330
LOG=Y
R=dslomov@chromium.org

Review URL: https://codereview.chromium.org/624013005

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@24472 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Update unicode to 7.0.0.

And do not use code points with PATTERN_* property for identifier start.
Maintain that \u180E is a white space character.

BUG=v8:2892
LOG=Y
R=dpino@igalia.com, mathias@qiwi.be

Review URL: https://codereview.chromium.org/638643002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@24473 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Merge remote-tracking branch 'upstream/bleeding_edge' into bleeding_edge