native profiling support

only works with Linux for now
change target name, add cachegrind target
rebase_fixup
make: streamline native targets

The new target names are easier to remember / decipher:

term
term-cachegrind
term-gprof
term-valgrind

all
all-cachegrind
all-gprof
all-valgrind
all-debug

eval-gprof
eval-cachegrind
add variables for gprof, cg_annotate
Add include paths automatocally for USEMODULES

Application developers use `$(USEMODULES)` in their Makefiles to have
the relevant functionally automagically added to their apps. This even
does basic dependency tracking by means of `Makefile.dep`.

But an important thing is missing: the automatic adding of include
paths. This is inconvenient, error prone, and will hinder the RIOT core
developers in future to change folder structures.
Merge pull request #798 from Kijewski/usemodule-includes

Make: Add include paths automatically for USEMODULES
Fix rpl app for clang
Remove duplicate function definition in queue.h
make: Add DEFAULT_MODULE and DISABLE_MODULE

Closes #926
Add DISABLE_MODULE test
Merge pull request #769 from authmillenon/fix-rpl-app-for-clang

rpl: Fix RPL app for clang
Merge pull request #965 from authmillenon/remove-queue-duplicate

core: Remove duplicate function definition in queue.h
Add DISABLE_MODULE += auto_init to tests
Fixup for #798
Merge pull request #940 from Kijewski/issue-926

make: Add DEFAULT_MODULE and DISABLE_MODULE
examples/hello-world: return instead of busy loop.
Merge pull request #973 from LudwigOrtmann/examples_hello-world_update

examples/hello-world: return instead of busy loop.
Merge pull request #789 from LudwigOrtmann/native_gprof

native profiling tools support
Add `pthread_barrier_*` functions

Compare [`pthread_barrier_init`][1].

  [1]: http://pubs.opengroup.org/onlinepubs/9699919799/functions/pthread_barrier_init.html