Initial commit for adding xpub-xsub test

first write of test case for pub-sub tracing
known as the espresso pattern
(http://zguide.zeromq.org/php:chapter5#Pub-Sub-Tracing-Espresso-Pattern)
Refactoring xpub-xsub test

cleanup and refactoring of test case
Clean up code in xpub-xsub test

quick edits to comments and unsubscribe timeout
Added version check to xpub-xsub test

zmq version has to be greater or equal to 3.1.0
(xpub, xsub not supported in zmq 2.x.x)

also commit for travis
Moved xpub xsub socket creation

Creating xpub and xsub sockets after version check, not in beforeEach
Refactoring xpub-xsub test

removed beforeEach function in efforts to resolve current travis build
issues (which are not reproducible anyways)
refactored away from XSubXPubProxy function
use different inproc name to avoid INUSE error when called async in testing
...
Merge pull request #354 from f34rdotcom/zap_async_test_fix

Zap async test fix
use different inproc name to avoid INUSE error when called async in testing
...
Fix indentation issues

changing from a mix of tabs and spaces to all spaces
changing from 4-space wide indents to 2-spaces.
Merge pull request #352 from bluebery/xpub-xsub-test

added xpub-xsub test for pub-sub tracing
remove dup connection names to avoid collision in async calls in tests
another
Merge pull request #357 from f34rdotcom/test_socket_message_async_fix_b

remove dup connection names to avoid collision in async calls in tests
adjust settings to compensate for overloaded test servers on travis
Merge pull request #358 from f34rdotcom/increase_mocha_test_timeouts

adjust settings to compensate for overloaded test servers on travis
Travis, suck on this!
Merge pull request #359 from kkoopa/damn_you_travis

Travis, suck on this!