Add Google test based tests.

Initial testing include an "id test", which really just a
template test at this point, and a temperature sensor test.

The google test code is included in this commit. It will
eventually be taken out and replaced with a pull from a google
external repo.

Change-Id: I591818a9c169f4654fc8d8f17cf648f227d72545

tests/rdc_tests/gtest/WORKSPACE

@@ -0,0 +1,8 @@
+workspace(name = "com_google_googletest")
+
+# Abseil
+http_archive(
+     name = "com_google_absl",
+     urls = ["https://github.com/abseil/abseil-cpp/archive/master.zip"],
+     strip_prefix = "abseil-cpp-master",
+)