SAUL/phydat: parts per million support

sys/phydat: rename phydat_scale_to_str -> phydat_prefix_from_scale

drivers/sdcard_spi: use of ucrc16 by default

Useless consts removed.

drivers: Initial import of low-level QDEC driver interface

unittests/tests-core: Fix tests in loop not being executed

Correct some outdated documentation and make the name represent what the
function does today.

mtd_native: fix overlapping pages write check

driver/mtd_spi_nor: fix erase with unaligned addresses

tests/fatfs: Fix tests on native after configuration changes in #8272

pkg/ccn-lite: bump version to fix compile error

pkg/semtech-loramac: improve package documentation

boards/b-l072z-lrwan1: fix on boards LEDs

drivers/hts221: minor fixes

dist/tools/edbg: fix typo in comment

- LED1/2/3 macros were refering to LED0
- LED1/2/3 are not initialized in board init

TIM3 now use for QDEC instead of PWM,
TIM3 (PA6 & PA7 pins) and TIM4 (PB6 & PB7 pins) timers,

Signed-off-by: Yannick Gicquel <ygicquel@gmail.com>

* Test all QDEC devices

Signed-off-by: Gilles DOFFE <g.doffe@gmail.com>

Use TIM3 (PA6 and PA7 pins) and TIM4 (PB6 and PB7 pins) timers.

Signed-off-by: Gilles DOFFE <g.doffe@gmail.com>

drivers: alphabetically sort the list of drivers in Makefile.include

Add periph_qdec to native native board features.

Signed-off-by: Gilles DOFFE <g.doffe@gmail.com>

* Add support for the STM32 encoder interface
* The STM32 only supports X2 and X4 modes.
* Enable interrupt handler on counter overflow
* Add simple test code for QDEC based on nucleo-f401 board

Signed-off-by: Gilles DOFFE <g.doffe@gmail.com>

* Add support for the native encoder interface
* Native QDEC is there mostly for simulation
* Calling code will have to simulate QDEC increment/decrement

Signed-off-by: Gilles DOFFE <g.doffe@gmail.com>

QDEC interface enables access to CPU peripherals acquiring quadrature
signals.

Signed-off-by: Gilles DOFFE <g.doffe@gmail.com>

efm32: Use different values for each unsupported ADC res

gnrc_netreg: Revert #8517 partly

make: add flag for no-implicit-fallthrough in CXXFLAGS

cpu: efm32: fix typo in cpus.txt

sys/can: fix compiler warning due to usage of potentially uninitialized variables