Added AUTHORS and CONTRIBUTORS and update LICENSE file

BUG:24665293
Change-Id: Id6a5eda4288614cd10052d6582acf29994b111cb
Reviewed-on: https://weave-review.googlesource.com/1306
Reviewed-by: Vitaly Buka <vitalybuka@google.com>
diff --git a/libweave/AUTHORS b/libweave/AUTHORS
new file mode 100644
index 0000000..e016204
--- /dev/null
+++ b/libweave/AUTHORS
@@ -0,0 +1,7 @@
+# This is the official list of The Weave authors for copyright purposes.
+# This file is distinct from the CONTRIBUTORS files.
+# See the latter for an explanation.
+# Names should be added to this file as:
+# Name or Organization <email address>
+# The email address is not required for organizations.
+Google Inc.