Add the vendor/ path, and add git submodules to the appropriate

subdirectory paths under vendor/

The intent is to make use of the golang 1.6 VENDOR extension
to build. As seen, the bare example does not correctly build
using bazel in this mode.

.gitignore

@@ -1 +1,5 @@
-bazel-*
+bazel-bazel-*
+bazel-bin
+bazel-genfiles
+bazel-out
+bazel-testlogs