Remove circular dependency in io

add file-lines

core/io/files/files.factor

@@ -3,7 +3,7 @@
 IN: io.files
 USING: io.backend io.files.private io hashtables kernel math
 memory namespaces sequences strings assocs arrays definitions
-system combinators splitting ;
+system combinators splitting sbufs ;
 
 HOOK: <file-reader> io-backend ( path -- stream )
 
@@ -157,3 +157,8 @@ HOOK: binary-roots io-backend ( -- seq )
 PRIVATE>
 
 : walk-dir ( path -- seq ) [ (walk-dir) ] { } make ;
+
+: file-lines ( path -- seq ) <file-reader> lines ;
+
+: file-contents ( path -- str )
+    dup <file-reader> swap file-length <sbuf> [ stream-copy ] keep >string ;

core/io/io.factor

@@ -1,7 +1,7 @@
 ! Copyright (C) 2003, 2007 Slava Pestov.
 ! See http://factorcode.org/license.txt for BSD license.
 USING: hashtables generic kernel math namespaces sequences strings
-    continuations assocs io.files io.styles sbufs ;
+    continuations assocs io.styles sbufs ;
 IN: io
 
 GENERIC: stream-close ( stream -- )
@@ -90,6 +90,3 @@ SYMBOL: stdio
 
 : contents ( stream -- str )
     2048 <sbuf> [ stream-copy ] keep >string ;
-
-: file-contents ( path -- str )
-    dup <file-reader> swap file-length <sbuf> [ stream-copy ] keep >string ;