[ADD] JS widgets reference documentation

Also fixed Widget#alive's behavior and tested it
[ADD] port webclient RPC doc from web/doc
[FIX] sphinx 'project' value

The project name automatically gets the release and the literal string
"documentation" appended by default (and "html_title" can be set to generate a
title differently), so having "documentation" set in the project variable
duplicates it in the page title.
[FIX] JS tutorial
Merge pull request #2375 from odoo-dev/8.0-webclient-doc-xmo

Port web client tutorial fully (-ish), improve JS doc.
[FIX] Can not execute line when stop date is EARLIER than current date
[FIX] migration: test if package is installed using its state.

checking if there is an installed version set is not enough because this field is not reset when the module is uninstalled
Merge pull request #2955 from odoo-dev/8.0-wmsmrpdatefix-jco

[FIX] Can not execute line when stop date is EARLIER than current date
[FIX] ir_actions: ids of unlink method can either be an ID list or one ID
[IMP] gamification: avoid sending twice emails in cron

When the cron is running on a database with a large number of goals (e.g. website_forum with thousands of users), it's possible the CPU time is exceeded and we may have a rollback after sending some emails (for granted badges).
To avoid sending twice emails, commit in cron mode after each reward.
[FIX] point_of_sale: prevent empty order creation as they are not accepted by the backend
[FIX] website_sale: save the company in street and the street in street2.

The old behaviour was not better, because when we print the invoice, the order was ugly:
    Name
    Street
    Company name
    Country

Now we will have:
    Name
    Company name
    Street
    Country

This patch is not retro-compatible:
   Old partners will see the address in company name and vice-versa.
   Need to update view and switch street field and street2 field
[IMP] website_event: add mail subtypes

Add published and unpublised mail subtypes, to track events publication, and to be able to follow these subtypes
Merge branch '8.0' of https://github.com/odoo/odoo into 8.0