This is useful for BitFields that are bools.

Additionally, VCacheEnhance has been added to UVAT_group1.  According to YAGCD, this field is always 1.

TVtxDesc also now has separate low and high fields whose hex values correspond with the proper registers, instead of having one 33-bit value.  This change was made in a way that should be backwards-compatible.

Additionally a new ClipDisable union has been added (though it is not currently used by Dolphin).

This value will be used in the register description; so expose it in a way that can be re-used instead of calculating it in 2 places later.

Additional changes:
- For TevStageCombiner's ColorCombiner and AlphaCombiner, op/comparison and scale/compare_mode have been split as there are different meanings and enums if bias is set to compare.  (Shift has also been renamed to scale)
- In TexMode0, min_filter has been split into min_mip and min_filter.
- In TexImage1, image_type is now cache_manually_managed.
- The unused bit in GenMode is now exposed.
- LPSize's lineaspect is now named adjust_for_aspect_ratio.

BPMEM_TEV_COLOR_ENV + 6 (0xC6) was missing due to a typo.  BPMEM_BP_MASK (0xFE) does not lend itself well to documentation with the current FIFO analyzer implementation (since it requires remembering the values in BP memory) but still shouldn't be treated as unknown.  BPMEM_TX_SETMODE0_4 and BPMEM_TX_SETMODE1_4 (0xA4-0xAB) were missing entirely.