New README.md

@seriousamlqz, @yzhang90, @grosu Please review

@grosu, please assign someone who knows better than me to write the Static Weaving Section: I don't use that option.
I have now explained what this ```-usedb``` option does. @grosu, if you insist on keeping these properties as part of the JavaMOP, I can very easily do so. I don't think this is in our best interest, though, on the long term, as we'd be duplicating them in multiple place in our various repos. We currently don't have infrastructure to keep these various repos in synch, and that is why I prefer to pull them from a central location for now. We already had issues recently when multiple locations for the properties diverged independently.