Feature request: Command line output option that doesn't require intensive deserialization

[Holmes5]

I'd like the option to use the ngt search command line tool programmatically, as it is faster than the Python bindings. However, the work needed to convert the command line output back into arrays of floats appears to be larger than the savings you would get from using the command line implementation. It would be convenient if there was an option to output the query responses to a file (or stdout) in a binary format like HDF5.