Replace Ohloh References with Open Hub

When referring to the web application and pages in the web application, "Ohloh" is replaced by "Open Hub".  However, the code base is called "Ohloh", so this component of the open source code base is still the "Ohloh API"
Update README.md
OTWO-3189: Change http://ohloh.net -> https://openhub.net
OTWO-3189: Rename meta.ohloh.net -> blog.openhub.net
OTWO-3189: Rename ohloh.net email address to openhub.net