The README links to documentation for output options and compressor options but these web pages seem to be out of date.

I don't know how serious this is, but I've run into at least the following inconsistencies:

• preamble seems to be supported as an output option, but it's unlisted.
• ie_proof is listed as an output option, when it should be screw_ie8 (This actually causes errors when I try to run uglifyjs.minify.)
• pure_getters seems to be supported as a compressor option, but it's unlisted.