Unify source of camera geometry data

Due to parallel development, camera pose information ended up being
populated in two constants files. This makes //y2019/vision:constants
the source for all of the constants.

Also, because the camera 19 calibration was done as if it was a front
camera, I had to negate its x/y position and offset the angle by 180
degrees.

This commit also adds validation for //y2019/vision:constants.cc to
ensure that it is not accidentally changed in a way that the codegen
cannot account for.

Change-Id: I85654d973e15ae7bf76589be63c3d0eaf72c3a45
diff --git a/y2019/vision/constants_formatting_test.sh b/y2019/vision/constants_formatting_test.sh
new file mode 100755
index 0000000..a74a988
--- /dev/null
+++ b/y2019/vision/constants_formatting_test.sh
@@ -0,0 +1,4 @@
+#!/bin/bash
+# The constants file should not have changed in a way that will not be preserved
+# when we rerun the codegen.
+diff $1 $2