fix rotation regression for Luma8

part of #27. This is an issue with get_matrix after a rotation.

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "rxing"
-version = "0.4.0"
+version = "0.4.1"
 description="A rust port of the zxing barcode library."
 license="Apache-2.0"
 repository="https://github.com/rxing-core/rxing"

src/luma_luma_source.rs

@@ -134,7 +134,8 @@ impl Luma8LuminanceSource {
             }
         }
         self.data = new_data;
-        self.dimensions = new_dim
+        self.dimensions = new_dim;
+        self.original_dimension = (self.original_dimension.1, self.original_dimension.0);
     }
 
     fn transpose(&mut self) {