function subst(array &$old,$new) {
		if (is_string($new))
			$new=[$new];
		foreach ($new as $hdr) {
			$old=preg_grep('/'.preg_quote(strstr($hdr,':',TRUE),'/').':.+/',
				$old,PREG_GREP_INVERT);
			array_push($old,$hdr);
		}
	}
function subst(array &$old,$new) {
		if (is_string($new))
			$new=[$new];
		foreach ($new as $hdr) {
			$old=preg_grep('/'.preg_quote(strstr($hdr,':',TRUE),'/').':.+/',
				$old,PREG_GREP_INVERT);
			array_push($old,$hdr);
		}
	}
function subst ( array & $ old , $ new ) { if ( is_string ( $ new ) ) $ new = [ $ new ] ; foreach ( $ new as $ hdr ) { $ old = preg_grep ( '/' . preg_quote ( strstr ( $ hdr , ':' , TRUE ) , '/' ) . ':.+/' , $ old , PREG_GREP_INVERT ) ; array_push ( $ old , $ hdr ) ; } }
Replace old headers with new elements
@return NULL
@param $old array
@param $new string|array
Replace old headers with new elements