transport/unix: Implementing connect timeout
transport/unix: Implementing connect timeout

This timeout is not strictly necessary for unix socket, but will be
useful later for other types of transports.

Change-Id: I2c3b155e0e75da4a127fffba2fecb964f2d8eff1

cawka/packaging-ndn-cpp-dev,cawka/packaging-ndn-cpp-dev,cawka/packaging-ndn-cpp-dev,cawka/packaging-ndn-cpp-dev