Change "%s" in qsprintf to exclude non-BMP characters
Ref T1191. Make %s in qsprintf reject non-BMP characters. Introduce %B for escaping binary strings.
Basically, this just makes "yes, I want to put binary data in this column" explicit.
Test Plan: See next diff for test coverage in Phabricator.
Reviewers: btrahan, arice
Reviewed By: arice
CC: chad, arice, aran
Maniphest Tasks: T1191
Differential Revision: https://secure.phabricator.com/D8315