at86rf2xx: correct rssi

dist/tools: add lazysponge tool

Remove file management from `genconfigheader` script and use `lazysponge` in
Makefile.include.

Use --verbose option when in non QUIET building mode.

Write stdin to <outfile> if it is different from the previous content.

If data provided in stdin is the same as the data that was in <outfile>, it is
not modified so `last modification date` is not changed.

boards: Extended/fixed SPI config for STM32 Nucleo-64 boards

tests/lwip_sock_*: fix compilation error

cpu/stm32_common: add PUF SRAM feature to makefile

boards/pba-d-01-kw2x: use OpenOCD-supplied config

at86rf2xx: Move flags from netdev to radio

gnrc_sixlowpan_iphc: cleanup NHC encoding

boards: Harmonized UART config of Nucleo-64 boards

boards/stm32f103c8: update flash flags for DFU

nimble: deactivate -Wunused-function with LLVM/clang

When building `nimble` with LLVM/clang the function
`ble_ll_adv_active_chanset_is_sec()` in `ble_ll_adv.c` is reported to
be unused, it is used within an assertions and `ifdef`s within that
file though. So this just disables that warning.

make: provide support for listing supported and blacklisting toolchains

Assuming `TOOLCHAIN_SUPPORTED` is provided by the board and
`TOOLCHAIN_BLACKLIST` by a module or `pkg`, this outputs the fact that
a toolchain is not supported or blacklisted in a similar manner as
(un-)supported features and boards are.

 dist: move testrunner to pythonlibs as package 

The latest bootloader has new usb device id and needs different
parameters to flash a RIOT image using `dfu-util`.

- nucleo-f334r8:
  - Added USART1 and USART3 config
- nucleo-f401re:
  - Changed order of UARTs to match the other boards
- nucleo-f410rb:
  - Added USART6 configuration
  - Fixed incorrect DMA settings (according to reference manual of the MCU)
- nucleo-f446re:
  - Changed order of UARTs to match the other boards
- nucleo-l152re:
  - Changed order of UARTs to match the other boards

The result of this harmonization is, that the first UART is always USART2, the
other USARTs are added in ascending order.

pkg: cmsis-dsp: fix -Wunknown-attributes for LLVM

Apparently LLVM doesn't know the `optimize` attribute.

boards/sensebox: Add support for SenseBox board

make: Makefile.include: Remove -Wno-implicit-fallthrough

frdm-k64f: Add SAUL ADC configuration

frdm-k64f: Update ADC configuration 

cpu/lpc2387: Fixed documentation and bugs preventing use of LLVM