Release Version 2.4.0.2
Bump version to 2.4.0.3dev
 Update to Nereid 2.4.0.8 style

This patch updates nereid-checkout to use the updated
testing pattern of nereid 2.4.0.8 which follows the
style of tryton core.
Add .travis.yml to ensure CI
Migration to Tryton 2.6 Active Record pattern

* Bump version to 2.6.0.1dev
* Adds audit and xmltests command to setup.py.
Send emails only when sale is placed via web

* Cherry picked from 2.4 series
Release version 2.6.0.1
Merge version 2.6.0.1