boards: removed deprecated netif initializations

ng_fib: fix fib_print_address typo

native: irq: Get rid of dINT() and eINT()

extended the documentation for the ng_networking example

Get rid of internal usage of the old IRQ
API and keep it's implementation while
waiting for other modules to kill it.

ng_netreg: warn about context overwrite

native: timer: synchronize HWTIMER_SPIN_BARRIER with native timer min resolution

ng_pktbuf: new default packet buffer implementation

ng_sixlowpan: fix the kaputt-reviewed fixes

net: removed deprecated non-gnrc netapi

This simplifies the `ng_pktbuf` API by adding a new function
`ng_pktbuf_mark()` which takes over some functionality of
`ng_pktbuf_add()`. `size == 0` for `ng_pktbuf_add()` is now illegal.

shell: sc_icmpv6_echo: prepare for stupid users

shell: sc_icmpv6_echo: don't fail if packet buffer is full

ng_sixlowpan: Fixes

make: remove scan-build folder in clean

cpu: cortexm_common: set pendSV to default priority

boards: added support for the Nordic nRF51 Dongle

gnrc: rename ng_netconf to ng_netopt

cpu/stm32f3: PWM driver, some corrections.

dist: make drone build script fail if gh label not set