maxLineLen and ASCIIOnly options support

When I was working on my project I found that "max_line_len" and "ascii_only" options is supported by UglifyJS but not grunt-contrib-uglify. They are important for me so I have simply added this two options and docs for them.

Also, I am not sure about any test, it just works. Additionally, when I pulled repository I was unable to pass tests: half of them tries to compare "\r\n" to "\n" and fails. Please, point me in a right way if test is necessary. Thanks.