This is the map builder for Arrays of Arrays of Double. It is not to be confused with the builder for Arrays of Double. It requires 3 memebers to
be implemented in the final type BuffT, newBuff and fromArrayArrayDbl.
BuffT can be inbuilt Jvm type like ArrayBuffer[Int] for B = Int and BB = Ints, or it can be a compile time wrapped Arraybuffer inheriting from
BuffProdHomo.
BuffT can be inbuilt Jvm type like ArrayBuffer[Int] for B = Int and BB = Ints, or it can be a compile time wrapped Arraybuffer inheriting from
BuffProdHomo.