gh-1838 removed check for isPipe from Stream::isSeekable
gh-1838 removed check for isPipe from Stream::isSeekable

JoeBengalen/Slim,akrabat/Slim,iinux/Slim,Sam-Burns/Slim,slimphp/Slim,iinux/Slim,iinux/Slim,juliangut/Slim,RealSelf/Slim,foxyantho/Slim,dopesong/Slim