Prepare refactoring
in msg_send_receive: return result from msg_send
Merge pull request #80 from authmillenon/sixlowpan_refactor

Refactoring and Fixing of sixlowpan module
Merge pull request #88 from mehlis/msg-send-return-type

in msg_send_receive: return result from msg_send
merged zkasmi/makefile_fixes to makefile_windows_fixes

Conflicts:
	Makefile.include