Pre-Release: sensors and cloud

This first pre-release has:

• Cloud connection (relayr at the moment)
• Sensors connected to the RPi
• Support for measurements, alarms and commands

Pending:

• Test the alarms (only dry soil tested)
• Command handler
• Actuators to control the watering system (Hardware implementation pending)
• Integration of button to manually trigger the watering system (Hardware implementation pending)

Wish list:

• Local DDBB and dashboard (over RPi's TFTT screen)
• Weather Underground climate comparison