Remove hardcoded configurations and replace with more robust mechanism for setup.

[Lotok]

Issue

At the moment the following information is hardcoded into the Arduino:

• MAC-address
• location
• room
• sensor type

For connection see #22

Solution

Configuration file should be on the Raspberry Pi.
Communication between Arduino and Pi over TCP.
Configuration in JSON format.

Scetch:

Requirements

• Arduino can ask Pi for config
• Pi can pick correct config for specific Arduino (over MAC-address)
• Pi can return correct data to Arduino