Fix default service directory address

Using 255.255.255.255 does not work on osx.
Merge pull request #99 from devin-c/fix_default_address

Fix default service directory address
Fix spec
Remove usage of tap
Remove usage of throw
Fix TTIN signal
Fix threading model
Remove last inproc socket in favor of IO pipe
Merge 'upstream/master' into fix_threading_model
Cleanup
Try to reproduce the bad file descriptor error
Fix bad file descriptor error

ZMQ was throwing a "Bad file descriptor" error when many requests are
made in a small time frame. This happened because each request creates a
new zmq context and a new socket within that context. By using a single
ZMQ context for all requests, the error dissappears.
Reconcile with feedback
Merge pull request #100 from devin-c/fix_threading_model

Fix threading model