Add a process which reads frames from the camera

Tested on a pi, and it captures something. Don't have a good way to look
if the data makes any sense or not.

Change-Id: I40c8c4e395fcf468f4381250c7b75a5e4bee0cc4
diff --git a/y2020/vision/BUILD b/y2020/vision/BUILD
index 021a466..2e3723d 100644
--- a/y2020/vision/BUILD
+++ b/y2020/vision/BUILD
@@ -1,7 +1,38 @@
 load("@com_github_google_flatbuffers//:build_defs.bzl", "flatbuffer_cc_library")
+load("//aos:config.bzl", "aos_config")
 
 flatbuffer_cc_library(
     name = "vision_fbs",
     srcs = ["vision.fbs"],
     gen_reflections = 1,
+    visibility = ["//y2020:__subpackages__"],
+)
+
+cc_library(
+    name = "v4l2_reader",
+    srcs = [
+        "v4l2_reader.cc",
+    ],
+    hdrs = [
+        "v4l2_reader.h",
+    ],
+    deps = [
+        ":vision_fbs",
+        "//aos/events:event_loop",
+        "//aos/scoped:scoped_fd",
+        "@com_github_google_glog//:glog",
+        "@com_google_absl//absl/base",
+    ],
+)
+
+cc_binary(
+    name = "camera_reader",
+    srcs = [
+        "camera_reader.cc",
+    ],
+    deps = [
+        ":v4l2_reader",
+        "//aos:init",
+        "//aos/events:shm_event_loop",
+    ],
 )