[FEATURE] ProgressListener and disabling cout/cerr debug messages from hdt-cpp

[nilesh-c]

• hdt-cpp uses a bunch of cout/cerr debug output and in Python it can be annoying to have those messages with no means to make this configurable. Since it's c++ extensions, I couldn't figure out any way to shut them up in Python code. I wrote a workaround for this that redirects cerr/cout to /dev/null here.
• Fully loading large files like DBpedia hdts can take a while, so I used hdt-cpp's StdoutProgressListener to get some progress output from the HDTManager::loadXXX methods. In the same commit here

Let me know if you find any of those useful and I'll send a PR. :)