Added support for sourcesContent property of source map
added hasOwnProperty check to avoid warnings
Don't unescape \x00 in regexes (it breaks IE8)
Move unescaping regexps under a codegen option (`unescape_regexps`)
Merge pull request #408 from danielstutzman/escape-null-in-regex

Don't unescape \x00 in regexes (it breaks IE8)
Merge branch 'master' of github.com:mishoo/UglifyJS2
v2.4.12
Merge branch 'sourcesContent' of https://github.com/arty-name/UglifyJS2 into arty-name-sourcesContent
Update source-map
Fix if_return dropping the alternative.  Close #413