Test for non-executable files with execute bit set.

* Install a build check to avoid regressions.
Flake8 already checks for NL at EOF (W292).
Remove execute flag from non-executable files.

* Targeted file extensions
  cpp, css, eot, html, jpg, js, json, less, map, md, png, scss, ttf, txt,
  yml, woff
* Other files:
  LICENSE, README
Merge pull request #568 from Renelvon/no_exc

[WIP] Remove execute bit from non-executable files. Install relevant build check.
Unit tests for node/contact.py.
Refactor Contact.

* Simplify __eq__ and derive __ne__ from __eq__.
    Implementing both __eq__ and __ne__ is redundant and error prone.
    One of them should be derived from the other, to guard against
    subtle errors.
* Implement __repr__ and derive __str__ automatically.
    Implementing __str__ but not __repr__ is considered bad practice,
    and makes debugging a bit awkward, because Python drops in a default
    replacement for the missing __repr__. However, if only __repr__ is
    implemented, then it will be used for both repr and str calls.
* Remove execute flag of node/contact.py.
Merge pull request #572 from Renelvon/sane_contact

Refactor and test node/contact.py
Extend database schema for orders refunds
Database Fix
Merge pull request #574 from hoffmabc/DBFix

Database Creation Fix
[FEATURE] deleted instructions for wrong port in Debian
[FEATURE] deleted instructions for wrong port in Ubuntu
Resolve Hostnames to IPs

This should eliminate DNS lookups everytime.
Merge pull request #577 from hoffmabc/DBFix

Resolve Hostnames to IPs
[FEATURE] Add comand openbazaar port
Build on Fedora
Fix some Fedora issues with OpenSSL
[FEATURE] Add command openbazaar port for OSX and GNU/Linux Ubuntu/Debian
[FEATURE] openbazaar port for OSX and GNU/Linux Ubuntu/Debian
Explicitly name vagrant box as trusty32.

To differentiate from trusty64.