[FIX] data dir when home is not a directory

Use site data dir instead of user data dir when user's home is not a directory.
Like system users created with /dev/null as home.

Stricter than before.
[IMP] qweb debug mode restricted to --dev mode

Also moved the set_trace call in top of render_node() function so it
makes more sense.
[IMP] Make translation todo's readable when hovered
[IMP] stock: allow float precision for quantity qty multiple

e.g. if orders with packages of 1/2 quantity
Merge pull request #1343 from vice/master

[FIX] data dir when home is not a directory
[IMP] [DATA] product: added default product.product data (Miscellaneous), consumable and available for the point of sale.
[UPG] web: upgraded font-axesome to version 4.2. New icons! Shiny! Lots of fun!
[IMP] sale, website_quote: expiration date is usefull even without using the website_quote module, therefore movign the field to the sale module. It has also be added to the email templates defined in sale and portal_sale, as well as in reports.
[IMP] crm, sale_crm: onboarding-related fixes
- lead name is now called Opportunity, clearer, added a placeholder on the form view;
- type (contact type) field is now dedicated to the group_delivery_invoice_address group.
It is set for technical groups only in base, then upgraded to the correct group in the
sale module that defines this group
[IMP] sale_crm: on opportunity form view, add a button linking to the
sales related to the current opportunity, using a stat button. Two fields are
introduced: opportunity_id on sale.order (automatically set when using the
make sale wizard), and sale_amount_total on the opportunity, function field
computing the total amount for the not canceled quotations related to the
opportunity.
[IMP] share: now restricted to the technical group, as this is a very
tricky feature. Also changed the order in the more menu.
[IMP] account, account_bank_statement_import: onboarding tips. Added 2 data files holding 2 tips for account, 1 for account_bank_statement_import.
[IMP] Event: Split Tickets
Attendees are created on SO confirm.
Attendees are directly created for FREE registrations and
Attendees are created and SO are linked to the paid tickets.
Improved code to make (5 attendees lines, 2 SO lines) when 3 vip tickets and 2 standard tickets are bought.

This commit fullfills the following Goals:

Goal 1 : When only website_event is installed, free registration should be possible from website.
Goal 2 : When only event and website_event are installed, badge report should be print for free registrations.
Goal 3 : When website_event_sale is installed, at that time on confirming the sale order, the subscription line are splited per attendees.
Goal 4 : Added code for attendees registrations through SO. Now from SO also the attendee's details for the event can be filled same as from website
[IMP] Improved and added code for adding and deleting attendees from MYCART when the quantity of Event products are increased or drecreased.
Added xpath