librfm69 (#28) ...

* Initial test
* Test and adjust for RFM69

Make broadcast address configurable

Fix interpreting RSSI for feedback to transmitter

Rename to librfm95, fix FSK Rx with response (#27) ...

- with the "shared" FSK FIFO, must first read payload and then send response :-/

Implement LoRa mode (#26) ...

* Prepare for LoRa mode
* Partial impl. of LoRa mode
- FSK mode still works :-)
* TX and RX in LoRa mode initially working
* Response from receiver to transmitter in LoRa mode
* Refactoring

RFM95 (#25) ...

- Use librfm95 instead of librfm
- Some improvements & fixes for RFM95
- Add "unblocking" timeout + minor improvements
- Let watchdog bark each 2 seconds instead of 8
  should consume only very little more power but allows to perform checks more frequently
- Slow down SPI for the breadboard wiring

Improve RSSI - output power control loop by averaging (#23)

Use radio module's timeout function instead of homebrew... (#22) ...

...which worked too but was more complicated. Simplify, simplify!

Fix function names

Use libsdc (#21)

Give display some more time to power up

librfm (#20) ...

- Initial changes to include static library
- Fix build and Makefile
- Include and implement now device and F_CPU independent library

Prepare moving radio module support to static library (#19) ...

- Move INT0 ISR back to main module, rearrange radio functions
- Refactoring: Move TX timeout handling back to main module

Narrow down SD card init failure/simplify solution ...

- with the radio breakout on the same SPI bus, first 'send idle' command fails
  but second attempt (and remainig intialization) succeeds reliably

Add SD card to transmit larger amount of data (#16) ...

- Correct timeout count
- Transmit first block read from SD card
- Receive data read from SD card and print it via USART
- Some minor fixes + improvements

Slow down TX attempts if receiver does not respond for a while (#17) ...

- reduces transmitter power consumption if receiver does not respond for a longer period of time

Even more refactoring! Even better! (#15)

Some more refactoring (#14)

Refactor imeout handling (#13) ...

- move related code to radio
- cancel timeout when "PayloadReady" arrives
- reduce timeout from 1 second to 100 milliseconds
- no delay before transmitting feedback to transmitter
- update README.md

Improve power management, save more power

Cosmetic changes to README.md and display

Cosmetic changes to README.md and display

Transmit output power and display it along with the temperature

Basic transmitter power management based on receiver RSSI

Receive with timeout

Send response (RSSI) from receiver to transmitter

Allow passing node address

Frequency deviation/receiver bandwidth (#8) ...

- 10/20 kHz is enough to remove temperature susceptibility
- fix display of negative temperature values

Better sprintf

Resolve suspectibility to temperature changes (#7) ...

- increase transmitter frequency deviation to 40 kHz
- increase receiver bandwidth to 80 kHz
- (almost) fix display of negative temperature values