Upgrade to OpenTracing 1.1 with SpanContext

[yurishkuro]

No description provided.

[coveralls]

Coverage increased (+0.8%) to 78.36% when pulling 6d7e3ea on back-to-span-context into ede24fa on master.

[coveralls]

Coverage increased (+0.8%) to 78.36% when pulling d1c0c5b on back-to-span-context into ede24fa on master.

[coveralls]

Coverage increased (+0.8%) to 78.36% when pulling 44934a8 on back-to-span-context into ede24fa on master.

[coveralls]

Coverage increased (+0.8%) to 78.36% when pulling 44934a8 on back-to-span-context into ede24fa on master.

[thepaulm]

This code causes pain right now in its current instantiation in tchannel. Lot's of laptops fail calls to socket.gethostname() because of ad-hoc ephemeral nature of the their hostname from the wifi. It's become common practice for devs to hard code their hostname and then add it to their /etc/hosts file to make this work.

I'd rather not have people who are approaching this code for the first time run into this. Can we perhaps do something like this:

try:
ip = socket.gethostbyname(socket.gethostname())
except:
ip = socket.gethostbyname('localhost')

[thepaulm]

Other than my request about the local_ip() function, this looks great!

[coveralls]

Coverage increased (+1.5%) to 79.113% when pulling 5ec2f68 on back-to-span-context into ede24fa on master.

[coveralls]

Coverage increased (+0.3%) to 84.486% when pulling 8c7140e on back-to-span-context into cd7ceb0 on master.

[coveralls]

Coverage increased (+0.3%) to 84.486% when pulling 9d4cdc7 on back-to-span-context into cd7ceb0 on master.

[coveralls]

Coverage increased (+0.3%) to 84.486% when pulling 899e1f8 on back-to-span-context into cd7ceb0 on master.

[coveralls]

Coverage increased (+0.3%) to 84.486% when pulling 24225f5 on back-to-span-context into cd7ceb0 on master.

[coveralls]

Coverage increased (+0.3%) to 84.486% when pulling 66427f2 on back-to-span-context into cd7ceb0 on master.