docs: Importing initial set of library documentation from wiki

To build documentation, doxygen (+graphviz dot) and sphinx-build are
required.  Manpages are build and installed during `./waf build` stage
if sphinx-build is present.

Documentation can be build using the following commands:

    # Full set of documentation (tutorials + API) in build/docs
    ./waf docs

    # Only tutorials in `build/docs`
    ./waf sphinx

    # Only API docs in `build/docs/doxygen`
    ./waf doxgyen

Change-Id: I4c08be08ca3e22068db54584f99467aa6cf38d04
Refs: #1462
diff --git a/README.md b/README.md
index e7c38a7..f846c24 100644
--- a/README.md
+++ b/README.md
@@ -2,10 +2,10 @@
 ---------------------------------------------------------------------------
 
 ndn-cpp-dev is a new implementation of a Named Data Networking client library written in C++.
-	
+
 ndn-cpp-dev is open source under a license described in the file COPYING.  While the license
 does not require it, we really would appreciate it if others would share their
-contributions to the library if they are willing to do so under the same license. 
+contributions to the library if they are willing to do so under the same license.
 
 See the file INSTALL for build and install instructions.
 
@@ -13,3 +13,6 @@
 http://redmine.named-data.net/projects/ndn-cpp-dev/issues
 
 
+## More
+
+Additional library tutorials and manpages are available in `docs/` folder.