hfeasy 0v8: one firmware for all devices

Allows you to setup gpio in the config webpage.
NOTE: Gpio numbers in the config should match the module physical pin number:

• LPB100 pin range is from 1 to 48
• LPT100F pins range is from 1 to 10

Updating:

1. Upgrade your device firmware using the webpage: http://ip/iweb.html
2. Go to the main config page http://ip/config and click "Device"
3. Select your device, hit apply, go back and "Save to flash and reboot"
4. Alternatively you can select device "Custom" and you'll be able to config GPIOs

Fixes:
Should fix #17

WARNING: Your config will be reset.