fix!(aliby): dimensions in tiler consistent with image

WHY IS THIS CHANGE NEEDED?:
- tiler dimensions are ctzyx, but image dimensions are tczyx by default.
  this leads to incorrect storage of shapes

HOW DOES THE CHANGE SOLVE THE PROBLEM?:
- re-arrange the dimensions in the shape property to match image
- justifying this for the purpose of getting ImageDummy to play well
  with Tiler

WHAT SIDE EFFECTS DOES THIS CHANGE HAVE?:
- this exposes technical debt: there are places in which the order of
  dimensions are hard-coded and later assumed like this, and leads to
  indexing dimensions by index rather than by name.  in addition, the
  assumed order of dimensions is inconsistent throughout tiler.  this is
  a recipe for confusion.  worth a refactor soon.

src/aliby/tile/tiler.py

@@ -358,7 +358,12 @@ class Tiler(StepABC):
             no of pixels in y direction
             no of pixels in z direction
         """
-        c, t, z, y, x = self.image.shape
+        # FIXME: TECHNICAL DEBT -- hard-coding dimension order.
+        # This is valid for dummy tiler and conforms to the default order
+        # in Image instances.  However, there is no guarantee that it will
+        # work with the other tiler instances.
+        # c, t, z, y, x = self.image.shape
+        t, c, z, y, x = self.image.shape
         return (c, t, x, y, z)
 
     @property