Backport double line field interlace

Created by: sonninnos

New stuff:

• Replaced current framerate halving double line frame with full framerate double line field
• Added core option "Remove Interlace Artifacts" which behaves best on static screens
  • Confusingly the option is named gfx_flickerfixer in confs and gfx_scandoubler internally, but according to the changelog it is neither:

• "Flicker fixer" renamed to "Remove interlace artifacts" (it really isn't same as flickerfixer or scandoubler)

Fixes:

• Sound filter type option was accidentally forced at "Automatic"
• More autozoom+centering solutions
  • Allow UAE internal centerings but prevent RA geometry sets in certain situations
• Random crash when changing resolution and interlacing at the same time in WB

Bonus:

• Core option unifications and reorganizings