directories: un-recurse get_files() and get_state()

These methods were previously called recursively and it seemed to cause
problems in some cases. The recursive nature of these functions not
bringing any notable advantage and `os.walk()` being of better style
anyway, I removed that recursive nature.

Hopefully fixes #421

core/tests/directories_test.py

@@ -13,6 +13,7 @@ from pytest import raises
 from hscommon.path import Path
 from hscommon.testutil import eq_
 
+from ..fs import File
 from ..directories import Directories, DirectoryState, AlreadyThereError, InvalidPathError
 
 def create_fake_fs(rootpath):
@@ -162,6 +163,20 @@ def test_get_files():
         else:
             assert not f.is_ref
 
+def test_get_files_with_folders():
+    # When fileclasses handle folders, return them and stop recursing!
+    class FakeFile(File):
+        @classmethod
+        def can_handle(cls, path):
+            return True
+
+    d = Directories()
+    p = testpath['fs']
+    d.add_path(p)
+    files = list(d.get_files(fileclasses=[FakeFile]))
+    # We have the 3 root files and the 3 root dirs
+    eq_(6, len(files))
+
 def test_get_folders():
     d = Directories()
     p = testpath['fs']