shell: renaming `isnumber` to `is_number` in sc_net_if.c

fix name collision on OS X by renaming
net: handle macro redefinitions for OS X

undefine macros and reorder header includes to get rid of system
defined macros on OS X

fixes #1165
msp430: fix missing members in `struct tm`

Closes #1150.
make: Remove `Makefile.unsupported`

This mechanism was replaced by #535. It was only used in one project.
Merge pull request #1173 from thomaseichinger/fix_rpl_udp_osx

native: net: OSX: Fix rpl_udp example
Merge pull request #1174 from Kijewski/remove-Makefile.unsupported

make: Remove `Makefile.unsupported`
native: initialize maybe uninitialized variable

fixes #1118
boards: fix license headers to LGPL

harmonises license headers in msb-430, msba2-common,
msba2 and wsn430-common

fixes #1160
Merge pull request #1176 from thomaseichinger/fix_1160

boards: fix license headers to LGPL
core: improved doxygen documentation

improved files complient to issue #950
- thread.h
- flags.h
- debug.h
- crash.h
Implement core unittests
unittests: Move tests-core into subdirectoy
native: refactor one debug/errx use in irq_cpu.c
native/tramp.S: use ret instead of manual return
github: added CONTRIBUTING.md
README.md: make link a markdown link
Merge pull request #1064 from mehlis/CONTRIBUTING

github: added CONTRIBUTING.md
board: Initial import of the UDOO board

- fixed comment style and bracketing
- disabled newlib nano, added mac support
- fixed OSX compatibility in Makefile.include
Merge pull request #958 from haukepetersen/doxygen_fix_core_1

core: improved doxygen documentation
examples/tests: blacklisted udoo board

blacklisted for:
- ccn-lite-client
- ccn-lite-relay
- rpl_udp
- test_net_if
- test_pnet