Added per-task curdir. and chdir, pager_read/write, mmap and munmap calls.

They look like what they should look like, but untested.

tasks/fs0/src/memfs/file.c

@@ -16,7 +16,7 @@
 
 #if 0
 
-/* 
+/*
  * FIXME: read_write() could be more layered using these functions.
  */
 void *memfs_read_block(struct vnode *v, int blknum)

tasks/fs0/src/memfs/memfs.c

@@ -66,6 +66,12 @@ int memfs_format_filesystem(void *buffer)
 	INIT_LIST_HEAD(&sb->inode_cache_list);
 	memfs_init_caches(sb);
 
+	/*
+	 * TODO: Make sure root vnode has a vnode number of 0 !!!.
+	 * This is used in early root lookup.
+	 */
+	BUG();
+
 	/* We allocate and fix a root inode so the sb is ready for mount */
 	sb->root = memfs_create_inode(sb);