Factor/To do/Specialized arrays

• Document io.mmap mapped arrays
• Document specialized-arrays.direct
• Functors should be better behaved: record definitions in current source file, make see work on a functor, make see on generated words less ugly perhaps
• 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

Done

• Phase out float-array
• Phase out words like >c-float-array, c-float-array> etc
• Maybe split them up into separate vocabs?