Cumulate quantities of similar dishes in KC report and Route sheet

[lamontfr]

Fixes #666.

Changes proposed in this pull request:

• order/models.py Order.get_kitchen_items() : cumulate quantities for dishes having the same component_group
• order/models.py Order.get_delivery_list() : cumulate quantities and concatenate remark for dishes having the same component_group.
• order/tests.py : added tests for multiple order items having the same side dish in a given order

Status

• READY

How to verify this change

1- Click on Kitchen Count in the menu
2- Generate orders for the day
3- Continue to print the Kitchen count and write down the quantities of each side dish in the summary near the top
4- Continue to Display a Route sheet for a route and write down the quantities of each side dish for a specific client
5- Go back to the Kitchen count orders list
6- Click to edit the order of the client chosen in point 4 above
7- Click on Add an order item
8- Choose the component group for the new order item to be identical to that of another side dish in the order
9- Set quantity = 1 and price = 2
10- Set billable to Yes
11- Click to update order
12- Click on Kitchen Count in the menu
13- Continue to print the Kitchen count and verify that the quantity for the side dish chosen in point 8 has increased by 1
14- Continue to Display the Route sheet for the route chosen in point 4 and verify that for the client chosen in point 4 the quantity for the side dish chosen in point 8 has increased by 1

[coveralls]

Coverage increased (+0.07%) to 94.967% when pulling f96456a on lamontfr:fix666 into fcbe341 on savoirfairelinux:dev.

[lingxiaoyang]

Verified.

Before PR:

After PR: