Preserving existing intdent

[yko]

Can beautifier preserve existing intdent (can be read from first line of source)?
Such option can be usefull when using js_beautify.pl from vim for intdenting blocks of code, that already have intdent at begin.
There's test for this case. If you approve this idea, i think i can write patch.

bt( " var a=preserve_first_indent;\nvar b = also_indented", " var a = preserve_first_indent;\n var b = also_indented" );