I'm trying to come up with a budget and bill of materials for acquiring a Nybble kit and everything else reasonably needed to work with it and program additional and higher-level functions. Besides the kit, do I need to buy anything more than a Raspberry Pi 3 B+, batteries, and charger? I haven't messed with RP much; is ssh access to it adequate for programming higher-level functions? And what tools are necessary to customize the firmware and data on the NyBoard?