docs: fix dimension order inconsistencies

REFERENCES:
- issue #62

docs/source/specifications/metadata.org

@@ -4,7 +4,7 @@ Draft for recommended metadata for images to provide a standard interface for al
 
 * Essential data
 - DimensionOrder: str
-  Order of dimensions (e.g., TCZYX for Channel, Time, Z,Y,X)
+  Order of dimensions (e.g., TCZYX for Time, Channel, Z, Y, X)
 - PixelSize: float
   Size of pixel, useful for segmentation.
 - Channels: List[str]

src/aliby/io/image.py

@@ -5,7 +5,7 @@ Image: Loads images and registers them.
 Image instances loads images from a specified directory into an object that
 also contains image properties such as name and metadata.  Pixels from images
 are stored in dask arrays; the standard way is to store them in 5-dimensional
-arrays: T(ime point), C(channel), Z(-stack), X, Y.
+arrays: T(ime point), C(channel), Z(-stack), Y, X.
 
 This module consists of a base Image class (BaseLocalImage).  ImageLocalOME
 handles local OMERO images.  ImageDir handles cases in which images are split