Record scrollbar movement in dialogs

[NQNStudios]

I forgot to stage one more replay system fix. This enables recording and replaying scrollbars in dialogxml scrollpanes.

[CelticMinstrel]

I have two general comments on this.

1. If every control now stores its ID, I think there are a bunch of code paths that could be simplified, where the control map is searched to get the ID of self.
2. I don't like that the scroll pane now requires an ID to function. I understand why it does (controls that don't specify an explicit Id gets a randomized ID, which won't work with replays), but can we come up with a different way to solve this?

[NQNStudios]

I think the ui's randomized ids are deterministic through a ui_rand object.

I added the id to this one because I had already recorded a replay where the id wasn't recorded, so I wanted to be able to edit the replay xml to retroactively set the name to something I knew it would be.

[NQNStudios]

@CelticMinstrel I removed the unnecessary 'name' attribute from about-boe and confirmed that a scrollpane without a name will record and replay correctly.

[NQNStudios]

@CelticMinstrel as you pointed out, controls in containers weren't getting their name fields set.

In order to do that while avoiding future merge conflicts, I cherry-picked my commit which makes containers resolve relative positioning in their elements.