Fixup for #685

- use DEVELHELP for native as well
- fix function name in documentation
- improve documentation language/spelling
Don't build PKGs twice
examples: fix rpl_udp README regarding invocation
Merge pull request #807 from LudwigOrtmann/examples_rpl_udp

examples: fix rpl_udp README regarding invocation
Include kernel.h for inet_pton for MSP-430
Merge pull request #790 from LudwigOrtmann/fixup_685

core: fixup for 685
Merge pull request #808 from authmillenon/inet_pton_msp_430_fix

Include kernel.h for inet_pton for MSP-430
Fix coding conventions in sys/transceiver/transceiver.c
tests: test_shell: call "make term" instead of hardcoded pseudoterm
Merge pull request #819 from kaspar030/tests_fix_shell_tests

tests: test_shell: call "make term" instead of hardcoded pseudoterm
Allow IEEE 802.15.4 addressing types for transceiver

IEEE 802.15.4 has two addressing modes: 16-bit short and the device's
EUI-64. Currently RIOT supports only sending of packets with 16-bit
short addresses via the transceiver interface. This patch allows at
least for the radio chips that support IEEE 802.15.4 to let the
application/upper layer decide which addressing mode to use.

Upper layer implementation will be implemented in follow-up PR to #460
Add getter and setter of long addresses to transceiver
Implement net_if module
Add shell commands for interface configuration
Add test cases for net_if module
test_shell: fix includes

malloc.h is not needed, apply coding conventions to others
Merge pull request #823 from LudwigOrtmann/test_shell

test_shell: fix includes
redbee-econotag: fix Makefiles

remove empty unsused Makefile.dep
add board include path to INCLUDES
Merge pull request #825 from LudwigOrtmann/redbee-econotag_Makefiles

redbee-econotag: fix Makefiles
sys/crypto: remove assert.h include

It is not used and most platforms don't have it.