lpc1768: cleanup Makefile

`cpu/lpc1768/Makefile` contains many lines that don't belong into this
file, but the maybe `Makefile.include`. Either way, this Makefile is
never called with these goals.
native: implement hwtimer removal
cpu - sam3x8e: fixed vtimer, added timer_set_absolute
boards: removed -lto flag and cleanup for udoo&arduino due
Merge pull request #1365 from haukepetersen/fix_cortexm3_ltoflag

boards: removed -lto flag and cleanup for udoo&arduino due
Merge pull request #1358 from haukepetersen/fix_sam3x_vtimer

cpu - sam3x8e: fixed vtimer, added timer_set_absolute
Merge pull request #1187 from Kijewski/mbed_lpc1768-makefile-cleanup

lpc1768: cleanup Makefile
Split RPL into core and mode related functions.
drivers - gpio: expanded gpio driver interface

- added functions for en|disabling a pins interrupt
driver - gpio: small adjustments
Merge pull request #1167 from fabianbrandt/rpl_base_split

Split RPL into core and mode related functions.
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.
Merge pull request #1368 from haukepetersen/fix_gpio_disableinterrupt

drivers - gpio: expanded gpio driver interface
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
make: allow chosing ld-like over gcc-like options

make automatically adds '-Wl,' to linker-options. Supply `LINKFLAGPREFIX :=` to avoid that.
Merge pull request #1359 from backenklee/ldovergcclink2

make: allow chosing ld-like over gcc-like options
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