Beta for the next spacebro-client without mdns support

With the 0.3.X version we removed the MDNS default support.
At first supporting mdns by default looks like a super idea. Unfortunately, it is not. node-mdns library is not well maintained and need help.
Thus, we decided to remove it.

The 0.3.X version will include a .use function which allow to plug the correct address resolver. Thus you will be able to use the spacebro-client on iOS / Android / Windows and Mac.

This means correct address resolver plugin have to be written. Think of them as vue plugin: https://alligator.io/vuejs/creating-custom-plugins/
or superagent plugins: https://github.com/visionmedia/superagent
or uptime plugins https://github.com/fzaninotto/uptime#writing-plugins

Next release should focus on fixing issues.