Option to skip first line

[bskubi]

I frequently work with tools that write .bed or .bedpe-type files with a header row. It would be really convenient to be able to skip the first row (or read from stdin) when using bedtools. I'm particularly running into this issue with bedtools shuffle at the moment. As far as I can tell, the necessary workaround is to duplicate the file sans header. Thank you for making and maintaining this great tool!