updates to readme

[adamhunter]

1. updated readme to include installing java 7 or 8
2. updated readme to instruct to install node or npm
3. updated readme instructions for config.json
   1. renamed example.config.json to config.json.example. This allows tab completion when writing the cp command or brace expansion (aka cp config.json{.example,})

[shaunlebron]

Cool thanks. Some thoughts:

• I think npm comes installed with Node, right? maybe we can update the link name to "Node & npm" and still just have it point to the node website.
• add the link to Java
• (not sure why the rename of example.config.json)

[shaunlebron]

thanks, we had some edits that had made it in prior to this one being merged, so just added the java version to readme to complete it.