vtimer: fix callback usage

There is no need to test the "handler" set in the vtimer struct, and
have some code executed then. We just can make the code to execute the
handler. To lengthy `if else if`, just a call.
native: implement hwtimer removal
applications: set stack size correctly

The correct stack size for all examples and test applications correctly.
KERNEL_CONF_STACKSIZE_MAIN is the correct stack size for any thread
using printf.

Also adapted black lists accordingly.
sys/ps: s/float/int for runtime

The high precision isn't needed, use per mille instead.
Circumvents printf problems on some platforms.

Also: prevent division by zero.
sys/ps: fix comment style, superfluous declaration
Merge pull request #1370 from OlegHahm/fix_stack_sizes

applications: set stack size correctly
Merge pull request #1352 from LudwigOrtmann/nofloat

sys/ps: don't use float for runtime calculations
Merge pull request #1351 from LudwigOrtmann/native_hwtimer

native: implement hwtimer removal
native: override INCLUDES w/ NATIVEINCLUDES

Currrently native overrides the object file targets, because it needs
the different include paths to interact with libc and the OS.

This PR simplifies their makefiles to only override the variable
INCLUDES, instead of overriding the targets.
setup git committer info in Travis

pkg/ Makefiles based on `Makefile.git` fail in Travis when attempting to apply patches with `git am` because no committer info is set.
This patch adds a dummy Travis username and mail in the 'install' step to satisfy git.
Merge pull request #1379 from benpicco/setup_git

setup git committer info in Travis
Extend CC2420 driver to comply with interfaces described in 'radio_driver.h'
Correction of HAL for CC2420 on concerned boards
core/msg: fix, optimize and improve

fixes:
fix race conditions by reordering dINTs
prevent null pointer dereference by adding forgotten target check
add forgotten eINTs
replace printf with DEBUG
fix debug messages

optimizations:
optimize pid access
reorder msg_send switches

improvements:
add debug statements
add missing return value to msg_send_to_self documentation
Merge pull request #1373 from Kijewski/easify-nativeincludes-usage

native: easify NATIVEINCLUDES usage
Merge pull request #1223 from rousselk/cc2420-extended-driver

CC2420: modify&extend driver to comply with API described in 'radio_driver.h'
x86: increase timeout in qemu's term

Currently `boards/qemu-i386/dist/term.py` expects QEMU to connect in
less than 5 seconds, which is plenty on any user machine. Travis CI,
which we use without paying a cent, sometimes fails to start QEMU in
this is timeframe, though.

This PR increases the timeout to one minute.
Merge pull request #1285 from LudwigOrtmann/msg_fixup

core/msg: prevent null pointer dereference
drivers/cc2420: fix logical error in cc2420_do_send function

Do the correct test in cc2420_do_send() function when analyzing
the result of cc2420_load_tx_buf()
boards/xx/driver_cc2420: fix race condition in CCA determination

Ensure that CS is active and IRQ disabled when querying CCA
on CC2420 (cc2420_get_cca() function).
Also do a little refactoring (renamed c variable into count,
and named the constant corresponding to RSSI "timeout").