ci: add clang-5.0 build job to Travis-CI

Add CI badge to README.md

Change-Id: Ieba0610e8aa05cb0dd09fc515d3c5d68a07b2af0
diff --git a/README.md b/README.md
index cd3e92e..328ed76 100644
--- a/README.md
+++ b/README.md
@@ -1,14 +1,20 @@
 repo-ng: Next generation of NDN repository
 ==========================================
 
-**repo-ng** is an implementation of a Named Data Networking data repository, and follows [Repo protocol](https://redmine.named-data.net/projects/repo-ng/wiki/Repo_Protocol_Specification).
+[![Build Status](https://travis-ci.org/named-data/repo-ng.svg?branch=master)](https://travis-ci.org/named-data/repo-ng)
 
-**repo-ng** uses [ndn-cxx](https://github.com/named-data/ndn-cxx) library as NDN
-development library, and uses sqlite3 as underlying storage.
+**repo-ng** is an implementation of a Named Data Networking data repository,
+and follows the [Repo protocol](https://redmine.named-data.net/projects/repo-ng/wiki/Repo_Protocol_Specification).
 
-**repo-ng** is an open source project licensed under GPL 3.0 (see `COPYING.md` for more
-detail).  We highly welcome all contributions to the repo-ng code, provided that they can licensed under GPL 3.0+ or other compatible license.
+**repo-ng** uses the [ndn-cxx](https://github.com/named-data/ndn-cxx) library
+as NDN development library, and sqlite3 as underlying storage.
+
+**repo-ng** is an open source project licensed under the GPL 3.0 (see
+`COPYING.md` for more details). We highly welcome all contributions to
+the repo-ng code, provided that they can licensed under GPL 3.0+ or other
+compatible license.
 
 See the file `INSTALL.md` for build and install instructions.
 
-Please submit any bugs or issues to [repo-ng issue tracker](https://redmine.named-data.net/projects/repo-ng/issues).
+Please submit any bugs or issues to the
+[repo-ng issue tracker](https://redmine.named-data.net/projects/repo-ng/issues).