Initial setup of site with import of languages and order states #1660

Import languages and order states as a part of initial setup of site.
This patch also converts the tests to be multi site.
Remove local XML files and use from mockstashop

Remove the duplicate XML files from this module and us the files directly from mockstashop
Import Customers from Prestashop as parties #1533

Import customers from prestashop as parties.
Also import countries and states and create caches for them in tryton
Import Products from prestashop #1534

Import products in prestashop as product templates in tryton
Import product combinations in prestashop as product variants in tryton
Import orders from prestashop as sale orders #1536

Import orders from prestashop to tryton
Update Order status on prestashop from tryton #1537

Update the status of orders from tryton to prestashop
Added views and minor fixes
Handle non availability of language

Handle the case where the language might not be available in the schema of prestashop (most probably due to version change)
Add ps_site to tree view of sale
Update the documentation to use latest screenshots
Merge pull request #9 from shalabhaggarwal/develop