Main

read_test: Add optional comment block to output input data one chunk per
file. This can be used to verify that the output data matches the input
data.

read_test: add new uring read method to read_test. It uses (requires)
liburing and a kernel >= 5.6.

Correct multiply by integer operator. Also add test cases.

Use boost::program_options for the main program.

Adding initial version of read_test.