olsrd: splitting IPv6/4 configuration and start scripts

This set of patches fixes issue #16 implementing the idea provided by @zioproto ( https://github.com/openwrt-routing/packages/issues/16#issuecomment-32892327 )

I think that the smartgateway part need some rework.
Before going on I would like to have some king of feedback.

/cc: @stargieg, @mmunz