GNRC includes this dependency implicitly, but if the NIB is used
isolated (as e.g. in its unittest suite) this dependency is missing.

shell: do not advertise reactively in 6ctx command

gnrc_ipv6_nib: add timeouts to routes

tests: add bluepill to gnrc_netif's insufficient memory list

After thinking about it a bit, I decided to remove the reactive
advertisement of context information all together in the shell command.
RFC 6775 does not explicitly forbids, but it discourages multicast RAs,
which would be the alternative.

tests: revert gnrc_netif2 Makefile to resolve merge conflict

gnrc_ipv6_nib: actually timeout a default router

While the GNRC_IPV6_NIB_RTR_TIMEOUT is properly handled, it is actually
never fired. Moreover, the router lifetime is set, but never read.

This removes the router lifetime and switches it out for an evtimer
to does the GNRC_IPV6_NIB_RTR_TIMEOUT event.

 gnrc_(*)2: rename to gnrc_\1

gnrc: remove legacy GNRC code

shell_commands: fix sc_gnrc_netif2 for MSP430

examples: gnrc_tftp: add bluepill board to insufficient memory list

gnrc_ipv6_nib: implement behavior for router discovery

(for now)

gnrc_lwmac: fix issues reported by cppcheck

gnrc_netif2: make more complexer functions not inline

cc110x: port to gnrc_netif2

gnrc_ipv6_nib: add exception in address resolution for SLIP