Factor/To do/Specialized arrays

• Document io.mmap mapped arrays
• Functors should record definitions in current source file
• Maybe mapped-file doesn't need to support sequence protocol
• FFI calls should call underlying>> on specialized arrays and direct arrays
• Specialized arrays of structs and unions
• Update basis and extra
• 2, 4 bit arrays
• Direct bit, 2 bit, 4 bit arrays
• look at <c-array> usage

Done

• Document specialized-arrays.direct
• stack effects for generated words
• byte array > specialized array words
• Phase out float-array
• Phase out words like >c-float-array, c-float-array> etc
• Maybe split them up into separate vocabs?