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.
Actually I thought about the same question. It is legal to use -merge without -n aspectName. JavaMOP will provide a default name called allmonitoraspect.aj. And -n aspectName has the same functionality as the -merge -n aspectName when given multiple properties. But I found it was hard to explain here.