Add bazel build system files.

Build everything with 'bazel build //...' and run all tests with
'bazel test //...'.

Change-Id: Ia912e999e33caa9b490002d639dc4c9a80034afc
diff --git a/.gitignore b/.gitignore
index a4d2b69..611aac2 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,5 +1,6 @@
 # Build artifacts
 out/
+bazel-*
 
 # IDE artifacts
 .idea/