Fix test/data/*.tga orientation

This re-ran imagemagick's convert program, but this time with an
"-auto-orient" option. See
https://issueexplorer.com/issue/ImageMagick/ImageMagick/3844

for i in {color,gray,nodither}; do \
  convert bricks-$i.png -auto-orient bricks-$i.tga; \
  done

The test/data/*.tga files only change in their 18th bytes, from 0x00
(bottom-to-top) to 0x20 (top-to-bottom).

Updates #67
diff --git a/test/data/bricks-color.tga b/test/data/bricks-color.tga
index 653641a..aa87427 100644
--- a/test/data/bricks-color.tga
+++ b/test/data/bricks-color.tga
Binary files differ
diff --git a/test/data/bricks-gray.tga b/test/data/bricks-gray.tga
index b9e3d2e..9cb0b24 100644
--- a/test/data/bricks-gray.tga
+++ b/test/data/bricks-gray.tga
Binary files differ
diff --git a/test/data/bricks-nodither.tga b/test/data/bricks-nodither.tga
index 8e3d662..898d255 100644
--- a/test/data/bricks-nodither.tga
+++ b/test/data/bricks-nodither.tga
Binary files differ