Changed Blob to a trait and made the indices Long.
Made value representations optional.
Added a class for convenient molecule building.
Fixed an embarrassing bug in ArrayBlob.
Changed the Dissector interface to include an offset.
Started moving primitive dissectors into their own class.
Moved the string dissector into primitives.
Started keeping track of piece offsets and lengths.
Added a way to conveniently build molecules.

Finally, the MD2 dissector looks somewhat pretty.
Added a convenience base trait for dissectors using molecule builders.

Also, for the first time the header dissector gets and uses the correct offset.