[avr] Removed usage of deprecated MCUSR

Since avr-libc 1.8.0 MCUSR is marked as poison as it was replaced by the
correct name MCUCSR.
Thus code still using the old MCUSR name does not compile anymore.

This commit replaces usages of former MCUSR by its new name MCUCSR and
modifies the alias fallback accordingly.
Added missing memb_free in queuebuf.c
Fix deallocation in queuebuf.c, case where QUEUEBUF_STATS is set
Output sha1sums of files used for simulation on fail
This helps reproducing results from the CI
Support setting the RELSTR
To build identical binaries the RELSTR must be identical, too.
Always compile verbose when running the CI
Merge pull request #821 from cmorty/pull/ci_debug

Make reproducing result from the CI easier
Merge pull request #782 from ejoerns/pull-req/avr-mcucsrfix

[avr] Removed usage of deprecated MCUSR
Merge pull request #857 from simonduq/fix-queuebuf

Added missing memb_free in queuebuf.c
packetbuf: Added function "packetbuf_holds_broadcast()" for checking whether the current packet is a
broadcast
packetbuf: Use packetbuf_holds_broadcast() all-over
framer-802154: Create without frame802154.c
framer-802154: Parse without frame802154.c
nullrdc: Removed dependency on frame802154.c
nullrdc: Get rid of compiler warning
framer-802154: Support spoofing
sicslowmac: Removed dependency on frame802154.c
Get rid of frame802154.c and most of frame802154.h
node-id: Functions for extra configuration data
llsec: Allow for sharing PRNG