Swipe: allow swipe drawing customization

[helios175]

Swipe rename:

• new methods without the ToRemove are added.
• the old ones are deprecated.

• canSwipe now should return which directions are allowed.

  Swipe underview:

• Allows for one or more definitions of "under views" (using the same mechanism as StandardRowSpec).
• An underview is created on swipe-start and updated on each new movement.

• Swipe underview binding passes a triplet: original view (to set alpha or other properties), swipe percentage, original data item.

  Swipe info:

• Swipe now informs of what direction it was swiped.