Add AU915 bandwidth and Adafruit Feather LoRa Boards

[testert1ng]

Extend most of the US915 configurations, changed frequencies for TX and RX.

[StereotypicalSquirrel]

I have successfully tested this merge on an Adafruit Adafruit Feather M0 RFM95 LoRa on AU915. ABP and OTAA both work with TTN.

I recommend the following changes:

1. Line 239 has a typo (Adfruit).
2. Line 249 has a typo (boadr).
3. Add either a pinmap or a comment for the Adfruit Feather M0 RFM95.

Correct pinmap for the M0 version is (Only difference is that DIO0 changes to pin 3):

Adafruit Feather M0 RFM95W loRa Radio 900MHz

This board uses the following pin mapping:

const lmic_pinmap lmic_pins = {
	.nss = 8,
	.rxtx = LMIC_UNUSED_PIN,
	.rst = 4,
	.dio = {3, 6, LMIC_UNUSED_PIN},
};

PIN6 and IO1 from the Adafruit board need to be connected before uploading the code.

Thanks

[testert1ng]

@StereotypicalSquirrel Thanks for your suggestion.

I have fixed the problems and added M0 pin map.

[ElectronicallyE]

Could this please be merged @StereotypicalSquirrel or @matthijskooijman? I've been using this branch as my primary library for over two months and it works perfectly with no issues. Being in Australia, the standard library does not work for AU915, meaning I have had to resort to using the code by @testerting.

[matthijskooijman]

This repository is now deprecated, see #297 for some more background. I'm grateful for your contribution, but it will no longer be merged. I'm recommending people to use the MCCI version of LMIC instead. If this PR addresses an issue that also exists in that version, I would encourage you to resubmit your contribution there, so it might benefit other users. I'm sorry for the inconvenience...