Allow configuration of which SD model to use (#263)

* Allow configuration of which SD model to use

Closes https://github.com/lstein/stable-diffusion/issues/49 The syntax isn't quite the same (opting for --weights over --model), although --weights is more in-line with the existing naming convention.
This method also locks us into models in the models/ldm/stable-diffusion-v1/ directory. Personally, I'm not averse to this, although a secondary solution may be necessary if we wish to supply weights from an external directory.

* Fix typo

* Allow either filename OR filepath input for arg

This approach allows both
--weights SD13 
--weights C:/StableDiffusion/models/ldm/stable-diffusion-v1/SD13.ckpt

scripts/dream.py

@@ -29,7 +29,10 @@ def main():
         width = 512
         height = 512
         config = 'configs/stable-diffusion/v1-inference.yaml'
-        weights = 'models/ldm/stable-diffusion-v1/model.ckpt'
+        if '.ckpt' in opt.weights:
+            weights = opt.weights
+        else:
+            weights = f'models/ldm/stable-diffusion-v1/{opt.weights}.ckpt'
 
     print('* Initializing, be patient...\n')
     sys.path.append('.')
@@ -418,6 +421,11 @@ def create_argv_parser():
         action='store_true',
         help='Start in web server mode.',
     )
+    parser.add_argument(
+        '--weights',
+        default='model',
+        help='Indicates the Stable Diffusion model to use.',
+    )
     return parser