Validate max_quantity on SaleWizard

When confirming a sale, we cannot select more batches than we sold to decrease.

Change-Id: I08872cf5f6d5c801e7bf911da8567eec3458bbc7
Set sensitivity of the button comment_info when opening saledetails

  When we open the dialog and go to comment tab, if we don't have any
comments or nothing is selected, after we push "Information" button,
we are creating a new comment, to avoid this behavior we are disabling the
button and only enable when we select some of comments

Change-Id: I4dbd8caeb7abdd78b83867b9c4b7725b1570319a