wsn430-v1_4b: don't always link cc2420
Add the ability to send a message to the current thread's message queue
(without raising an error)
ccnl: remove useless compare

This compare is useless for CCN lite in RIOT, because
a face has always an interface with index >= 0
Merge pull request #970 from rousselk/send_msg_intra_thread

core: Add the ability to send a message to the current thread's message queue
Merge pull request #1008 from mehlis/ccnl-serve-remove-if

ccnl: remove useless compare
changed pthread_self() to return thread IDs > 0
Fix test_pnet

fixes #829
Merge pull request #999 from OlegHahm/wsn430-v1_4_wo_radio

wsn430-v1_4b: don't always link cc2420
Merge pull request #830 from authmillenon/fix_test_pnet

tests: Fix test_pnet
fix doxygen documentation for clist.h, config.h, tcb.h and cib.h
Merge pull request #955 from thomaseichinger/fix_doc

core: documentation: fix doxygen documentation in cib.h clist.h config.h tcb.h
changed return value to 0 on lookup fail in pthread_self()
Merge pull request #1016 from BytesGalore/fix_cpp_pthread_id

posix:pthread c++11 changed pthread_self() to return thread IDs > 0
core: clist is a cyclic list
core: clist without explicit thread

Right now the core component `clist` is a generic cyclic doubly-linked list.
In the core it is used in `tcb_t::rq_entry`.
Further it is used `net_if.c`.

This commit removes the member `clist_node_t::data` which stored the
pointer to the `tcb_t` instance of which the clist is already a member.
The needless member added `sizeof (int)` bytes to every instance of
`tcb_t`.

In `net_if.c` the clist was used in a type-punned way, so that the
change won't affect it.