The previous texture_memory_alloc.hpp was written based on an
incorrect understanding of the "32-bit" and "64-bit" texture memory
address mapping.
The primary motivation is to rearrange the texture memory address map
so that "textures" (64-bit access) do not overlap with 32-bit
accesses, such as REGION_BASE or PARAM_BASE.
This enables alpha blending for both font_outline and
font_outline_punch_through.
I have also experimented more with 16-gray vs 256-gray--I have not
decided which between monochrome, 16-gray, or 256-gray I like the
most.
Perhaps a better test might be to test hanzi.
