Made pbobble parent of bublbust, as it seems to be more widespread and
more complete. Also fixed some ROM labels for bublbust.
Made tbyahhoo parent of mtwinbee as the latter has substantial content
removed rather than being localised, making it less complete.
Applied srcclean to JSON files in bgfx subtree.
* Made spot size parameters adjustable also increased samples from 2 to 3 scanlines for crt-geom-deluxe.
* Made horizontal interpolation adjustable.
* bgfx crt-geom-deluxe: Made phosphor decay smoothly to zero at specified cutoff time.
* bgfx crt-geom-deluxe: Added lowpass filter.
Added a "brightness boost" feature for the shadow mask that works by making the brightness ratio between bright and dark mask pixels closer to 1 for the brighter parts of the image.
Added clamping to zero so that underscanning produces a black border.
Added a "raster bloom" effect to crt-geom-deluxe that makes the image grow slightly when the average brightness of the screen is high, mimicking a common defect in CRTs.
This includes several aperture grille / shadow mask patterns. Note that these are all designed to be used on a display with RGB subpixel order, and may thus suffer if rotated or used with a BGR display.
