Added function pico_stack_recv_zerocopy_ext_buffer_notify()
Added compile time define
moved pico_olsr_init() to pico_stack_init()
OLSR disabled by default (fixed unit test failure)
Added better check for GCC version to enable fast byteswap
Added ifdefs to picoapp's olsr, so it does not try to compile when
disabled
Removed useless olsr_init
Merge pull request #209 from tass-belgium/development

Development branch: weekly merge
Fix memleak in DHCP server #210
Merge branch 'master' of github.com:tass-belgium/picotcp into dev-esp8266

- Should sort out the DHCP memleak