Support for PRT-HW WiFi thermostat

[iainbullock]

This release (v1.3.0) adds support for the PRT-HW WiFi thermostat, and adds the following functionality (for PRT-HW, maybe others):

• Setting timers for heating (should work for all models)
• Setting timers for hot water (for PRT-HW)
• Setting clock on thermostat with option offset (should work for all models)