Adding additional build system (waf)

NDNx and SSL locations can be controlled using --ndnx and --openssl
command-line arguments to ./waf configure

In addition to checking if SSL library works, check if selected/detected
SSL library matches with the one used during NDNx compilation

Change-Id: I972c35967a5035cf183551bf2379fb9af926ce07
Adding new-style unittest test scripts

Unittests can be run using `./waf test` can be run (after ./waf install)

Also, one can also run `nosetests' command directly, assuming PyNDN is
installed in a standard location or PYTHONPATH environment variable is
correct set up

Change-Id: I56b34c88ebe943bacd2f552f3bd64497931b3937