Kotlin I/O review/M11 fixes: Stream --> Sequence, recurse() returned back,

additional helpers like File.bufferedReader() and String.byteInputStream(),
copyRecursively / deleteRecursively were rewritten using FileTreeWalk,
FilePathComponents introduced as a replacement of FileIterator,
classes / methods / properties permissions fixed, Linux specific things,
resolveSibling rewritten using FilePathComponents

libraries/stdlib/test/io/ReadWrite.kt

@@ -71,12 +71,12 @@ class ReadWriteTest {
         writer.close()
 
         //file.replaceText("Hello\nWorld")
-        file.forEachBlock{ (arr: ByteArray, size: Int) ->
+        file.forEachBlock {(arr: ByteArray, size: Int) ->
             assertTrue(size >= 11 && size <= 12, size.toString())
             assertTrue(arr.contains('W'.toByte()))
         }
         val list = ArrayList<String>()
-        file.forEachLine{
+        file.forEachLine {
             list.add(it)
         }
         assertEquals(arrayListOf("Hello", "World"), list)