Add version to outgoing messages

- Added constant for version of release in constants.py
- Added 'v' value representing node's version number in send messages

This version number will help us see what version nodes are running on when diagnosing issues in the future.
Merge pull request #667 from hoffmabc/master

[CRITICAL] Add version to outgoing messages
Update 01 Physical Goods.md

Link to Ricardian Contracts info
Update 01 Physical Goods.md

Fix links to Peer-to-Peer Lending on OpenBazaar
Fix comments and unit test for market.py and style and docs

Fix comments and unit test for market.py and style
= squash =
[FEATURE] Fix logging-not-lazy and the whole set of comments to market.py and 2 links in docs

[FEATURE] Fix comments and quotes in a log

[FEATURE] Fix comments and unit test and style for market.py

[FEATURE] Fix comments and unit test for market.py

[FEATURE] Fix comments and unit test for market.py and style

[FEATURE] Fix comments, used imperative form for docstrings

= squash =
= squash =
[FEATURE] Fix comments and unittest for market.py and style and docs lincs

[FEATURE] Fix comments and unittest for market.py and style and docs lincs

Update market.py

Fix some comment

[FEATURE] Fix comments, used imperative form for docstrings

Fix comments, used imperative form for docstrings

Fix comments, used ran, etc

Test market, etc

Test market, etc

Update 01 Physical Goods.md

Fix links

Update 01 Physical Goods.md

Add master
test_market.py, test/myprog.py etc
Fix grammar, Obvious comment
Add timeout to resolve row lock bug

Simultaneous access to a row when writing and reading will cause an exception. This allows the proces to wait until it's available and then write instead.
Create only one zmq context to reduce overhead

Creating a zmq context for each PeerConnection object is wrong and creates a massive overhead.

Move context creation to parent class
Fix details comment
Remove redundant context creation
Fix executable bit check to work on Mac OS X.

* Ignore results from virtualenv folder.
Merge pull request #672 from Renelvon/mac_checkstyle

Fix executable bit check to work on Mac OS X.
Rename 08 Web of Trust.md to 02 Web of Trust.md
Rename 09 Dispute Resolution in OpenBazaar - Arbitration Market.md to 04 Dispute Resolution in OpenBazaar - Arbitration Market.md
Rename 06 Voting Pools in OpenBazaar.md to 03 Voting Pools in OpenBazaar.md
Create 05 Notaries-pools-certification-blinding.md
Update and rename 05 Notaries-pools-certification-blinding.md to 05 Notary Selection in OpenBazaar.md
Update README.md
Update README.md