examples/rpl_udp: use defaulttransceiver
Clean up test_irq (fix #943)
Make: exterminate 'clean' buildtarget

Closes #993.

We do not need to descend into the modules to know what to do on
`make clean BOARD=blub`. We can just invoke `rm -rf bin/blub`.

This PR only keeps the descending into the USEPKGs, since they might
want to delete cached/downloaded/extracted data.
Add missing doxygen for pthread funs and structs
pthread: fix spinlock
ccnl: use default transceiver
Merge pull request #969 from LudwigOrtmann/examples_rpl_udp_defaulttransceiver

examples/rpl_udp: use defaulttransceiver
Merge pull request #1001 from mehlis/ccnl-defaulttransceiver

ccnl: use default transceiver
examples: ccn-lite-client blacklist boards
examples: ccn-lite-relay blacklist boards
Merge pull request #1017 from Kijewski/issue-980

documentation: Add missing documentation for pthread functions and structures
Merge pull request #995 from Kijewski/issue-993

Make: exterminate 'clean' buildtarget clutter
pthread: implement reader/writer lock
Add pthread_rwlock test
Merge pull request #1018 from Kijewski/pthread-rwlock

pthread: implement reader/writer lock
examples: rpl_udp: blacklist boards
Merge pull request #1028 from mehlis/rpl-udp-blacklist

examples: rpl_udp: blacklist boards
Merge pull request #1030 from mehlis/ccnl-blacklist

examples: ccn-lite blacklist boards
Merge pull request #943 from Kijewski/issue-943

Clean up test_irq
native: update support for FreeBSD

works with FreeBSD 10.0 amd64/i386

fixes: #505