ENSCORESW-152. Committing the low cardinality and low row count caching framework into the core API. Implement the correct method from BaseAdaptor to have your values cached in local memory

Adding an iterator for subseqs to the Slice object. Means a lot of our code which deals with iteration of slices can delegate to this for its logic.

  Add date-stamp in output.

In warning():
  Add date-stamp in output.
  Make subroutine argument parsing work as for throw().
  Output message using warn() instead of to STDERR with printf().

now uses 1G for human rather than more than 4G

Using the new -rc_name and setup 2 classes sized according to the process from a 67 run of the pipeline. Both have been given room to grow. We will see if it's enough during production