Feature: (-tte) Add zoom level buttons to sprite aligner.

[PeterN]

Motivation / Problem

Sprite Aligner is hard to use; it shows the sprite at the current GUI zoom level, and offsets are always adjusted and shown for the maximum zoom level.

Description

Add extra zoom buttons to the sprite aligner window to allow selecting which sprite zoom level to display.

Offsets are scaled by the selected zoom level, and using the adjustment buttons takes this into account.

Additionally the selected sprite number is drawn in write in the sprite number list.

Lastly, the window is now resizeable.

Limitations

Checklist for review

Some things are not automated, and forgotten often. This list is a reminder for the reviewers.

• The bug fix is important enough to be backported? (label: 'backport requested')
• This PR touches english.txt or translations? Check the guidelines
• This PR affects the save game format? (label 'savegame upgrade')
• This PR affects the GS/AI API? (label 'needs review: Script API')
  • ai_changelog.hpp, game_changelog.hpp need updating.
  • The compatibility wrappers (compat_*.nut) need updating.
• This PR affects the NewGRF API? (label 'needs review: NewGRF')
  • newgrf_debug_data.h may need updating.
  • PR must be added to API tracker