avoiding N+1 queries
can't create a compra with proveedor consumidor final
upgrade ember

ember: 1.4.1-beta.1
ember-data: 1.0.0-beta.7.f87cba88
highlighting cliente/proveedor with text-danger when it has error
bugfix: this button was triggered when form submitted
new ember-data of persisting associations
set tipoId picker when not finding cliente/proveedor. This fixes #12
using pry
removed support for item.base
bugfix
added Bandango.numberForCurrencyHelper
refactored ItemBaseMixin
not allowing to destroy clientes that have compras/ventas
added autorizacionComprobante to Venta (client-side) and whitespace
moved comprobante info to shared orderable partial and added actions to compra
ModelBackedView now supports another way of binding model's attributes

if `get(“attributes”)` returns an object, it expects the key of each
attribute to be the object to bind those values
supporting compras.edit

and whitespace
fix for large comprobantes
preloading selects with model's values
upgrade chosen