Merge pull request #141 from timburke/pr-controller-v4

Update Controller Hardware to Version 4.0

Update controller board to rev 4.0.

- New version contains BTLE via Microchip RN4020 module
- Voltage supervisor with hard reset capability from bluetooth
or via microcontroller
- Current monitor for solar and external charging current
- Move 2.8V linear regulator and add RF filtering caps to fix RF
interference problems on GSM transmission.

Rename combined_controller to controller

We don't have different assembly variants anymore so the
combined isn't needed.

Update controller board to version 4.1

- Fix parasitic path through hw reset controller by passing control
signal through an optocoupler
- Replace Li-ion battery charger IC with constant current regulator
to allow for solar panel charging
- Add solar panel current measurement with 1 ohm shunt and differential
ADC lines

Fix battery charging and simplify reset circuit.

- Remove MOSFET from battery- to minimize R on GSM power supply
- Add constant current charger for charging from external source
- Update parts to compatible versions with lower cost D1-3, Q2,4

Update part sizing document.

Update HW Reset components for increased reliability based on SPICE

- larger RC network on discharge FET.
- increased required assert time to 120 ms.
- reset pulse length: ~100 ms @ 25C

Rename controller board from combined_controller

Update controller project file.

Remove autorouter file.

Update labeling on schematic

Add spice models for controller battery charging and hw reset

Update cosmetic changes to controller, remove wrong gnd plane in gsm_module

Remove ground plane from under BTLE module for antenna performance

Update gnd plane removal for larger antenna clearance

Add final trace connecting battery to 2.8V regulator.

Renamed part to controller.

Update board with final wiring and add additional io line to btle

Update V+ pour.