Create new contribution guide

[markhalonen]

We still have old contribution guides in this repo: https://github.com/relinc/SurePulse/tree/master/Libraries/DevGuide

And the README at least in the DataProcessor point to this guide. We should delete this guide and references to it, and create a new guide. It will be pretty easy, basically

• git clone https://github.com/relinc/SurePulse
• Import into Eclipse
• Install JavaFX plugins into Eclipse (if this is still necessary)