formatting issue
Load blank html file into iframe with result, so it shouldn't be themed by some browsers anymore.
Try to support CSS vendor prefixes between different browsers

This code does not cover the situation when ripping browser
already dropped prefixes and user browser still needs them.
ripper can now skip ripping css (for ripping whole documents)
target overrides the default node now, exposed some tools
readme updated to reflect latest changes
fixed bug in logic of skipCSS, added examples of ripper.copy