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.
destiny: wireshark revealed wrong seq/ack nr. in tcp handshake
Capturing the tcp handshake with wireshark revealed that the
sequence and ack nrs. are not rfc compliant.
I did the changes based on
http://tools.ietf.org/html/rfc793#page-52 to http://tools.ietf.org/html/rfc793#page-72
Fix all warnings for native and qemu-i386

Missing returns, unused variables (only used for debugging), empty
translation units, missing function prototypes, and GNU extensions.
Merge pull request #1301 from cgundogan/fix_tcp_handshake_seq_ack_rfc_compliancy

destiny: wireshark revealed wrong seq/ack nr. in tcp handshake
nativenet: change max packet size to 127

Real IEEE 802.15.4 transceivers have a payload of 127. Hence, for
testing - particular 6lowpan - it would make sense to have the same
limitation in nativenet. Especially to test fragmentation this is
helpful.
cpu cortex-m3_common: cleanup thread_arch.c
cpu - sam3x8e: added switch for newlib-nano specs
Merge pull request #1354 from OlegHahm/nativenet_packetsize

nativenet: change max packet size to 127
Merge pull request #1335 from Kijewski/fix-all-warnings-for-native-and-qemu-i386

Fix all warnings for native and qemu-i386
cpu - sam3x8e: fixed vtimer, added timer_set_absolute
Merge pull request #1356 from haukepetersen/fix_sam3x_newlibnano

cpu - sam3x8e: added switch for newlib-nano specs
Merge pull request #1357 from haukepetersen/fix_cortexm3_threading

cpu: cortex-m3_common: cleanup thread_arch.c
Introducing a source routing header for RPL.
Merge pull request #1218 from fabianbrandt/srh_rpl

Introducing a source routing header for RPL.
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