Defining targets for training images

Cleaning up commit message, and formatting on files.

More details:
- Includes ability to run command-line with or without bazel
- Also has write capability to flatbuffers for multiple targets
- Definition of targets and cameras, along with 3D point calcs
- Includes camera and target helper functions, along with defaults to get started
- Modified from Brian's version to work with python target_definition code, esp. to send multiple targets.

- Getting target_defintion set up for building flatbuffer data file.  Updated blue power point image to include full wings.
- Sample python code to do multiple image training, matching, and display results.  Includes sample images to play with
- Adding code to define masking polygons for removing features for training
- Tools to write out the target definition to flatbuffer
- Adds multi-target definition, and automates the process

Change-Id: Ibc90d51a129751bf456da6813b3e7cbc5e55901a
diff --git a/y2020/vision/sift/BUILD b/y2020/vision/sift/BUILD
index 5cfb6aa..e2b00f8 100644
--- a/y2020/vision/sift/BUILD
+++ b/y2020/vision/sift/BUILD
@@ -204,6 +204,7 @@
         "TrainingImage",
         "TrainingData",
     ],
+    visibility = ["//visibility:public"],
 )
 
 flatbuffer_cc_library(