Checkout process with mercado pago
- Buy order when user selects Pay
- Using MP modal for checkout -> i had to change navbar z-index 
- request configuration (only credit cards)
added pointsEnabled in Seller
added to BuyOrder: State(default PAYMENT_PENDING on creation) +
points(used/earned) + size
Stock returns a Map with available Size options for an Item
in initial data: one Seller set with pointsEnabled and another with
pointsDisabled
added pending and orderItem route
Item: GetAvailable size options +  mock size options map
BuyItem View -> showing item information, size options + Points usage
(grayed if seller has it disabled)
ItemController: sending sizeOptions +  pointsEnabled to buyOrder View
buy order detail with mercadopago button configured
siguiente button deleted, not used
Showing real buyer points and seller's pointsMoneyrelation
Creating item order after first step + showing information in summary
(point earned/ pendingAmount...)
after correct payment, changes state to PENDING_RECEPTION and assigns
points to order (not to buyer yet)
successful payment page
failed payment view
route pending deleted , treated as success
"keep on buying" redirects to home in success/error payment
Merge branch 'paymentProcess' into DEV

Conflicts:
	app/controllers/Application.java
	app/controllers/ItemController.java
	app/models/Item.java
	app/views/main.scala.html
	conf/initial-data.yml
	conf/routes