mishoo/UglifyJS2 — pull request #571 by rvanvelzen (2014-10-23 14:17:50+00:00)
Title: Fix #556

`\uFEFF` (ZERO WIDTH NO-BREAK SPACE) is removed when parsing, but was
un-escaped for the output when `ascii_only` was false.

When using
UglifyJS multiple times (creating packages from minified sources, for
example), this would lead to problems because the byte was removed when
parsing for the second time.