Table "row" object interface

[molpopgen]

The functions to return "row" structs have an option called decode_metadata. This name is wrong. It should be include_metadata. It may be preferable to simply remove the option entirely if we can figure out a way to safely obtain a slice based on the metadata.

Note: renaming the argument type does not break API. Removing it does.

[molpopgen]

Experiments show that we can indeed use slices here. This result is handy, as it allows some logic to be removed and a copy to be avoided.

[molpopgen]

https://stackoverflow.com/questions/26594733/capturing-lifetimes-in-rust-macro-rules

[molpopgen]

Even with the above hints, this could be tricky, changing to slices may be tricky...

[molpopgen]

The problem becomes iteration over the rows. Again, the GATS problem rears its ugly head.

Current solution: remove the argument, and just live with the performance hit for now.