Release 1.8

Summary of on-device changes: OS based on Linux 4.0 and Debian Stable (Jessie)

Improved device support: * Corrigo Ventilation support * Further mbus meter support * Support for Calio pumps * Support for Grundfos Magna 3 / CIM 200 pumps * Support for Thermia XL pumps * Now using VPN connections on port 443 to avoid abusive networks * Support for undocumented NIBE registers * Migrated Zabbix datatype to Trapper * Finalised Zigbee support