gnrc_netif: Fix compile errors when debug is enabled

gnrc_ipv6: fix packet snip switch-up

drivers: restore alphabetical order in Makefile.dep

bluepill: add i2c support

The only difference is that we changed the pins used by I2C_0.

tests: fix python E127 'continuation line over/under-indented for visual indent'

tests/lwip: fix python E711 comparison to None should be 'if cond is not None:'

tests/evtimer_msg: fix F841 local variable 'stop' is assigned to but never used

periph/flashpage: add flashpage_write_raw interface

ci: murdock: Replace hardcoded path by bindir variable

sys: net: add nanocoap

ci: murdock: fix output error on missing builddir after failed build

tests: set APPLICATION from folder name

drivers/kw2xrf: fix fall through

This was made visible by #7919. Broke build on GCC 7.2.

Probably a bug.

net/gcoap: Create confirm request infrastructure and adapt existing messaging

tests/xtimer_usleep_short: fix non set APPLICATION variable

examples: tests: optimize for NIB

gnrc_netdev: remove remaining files and references

Somehow, these files were forgotten in my big cleanup in #7925. This
fixes that.